diff --git a/src/openrct2-ui/interface/ViewportInteraction.cpp b/src/openrct2-ui/interface/ViewportInteraction.cpp
index 6bf2c91cfc..43d5f9b97e 100644
--- a/src/openrct2-ui/interface/ViewportInteraction.cpp
+++ b/src/openrct2-ui/interface/ViewportInteraction.cpp
@@ -599,7 +599,7 @@ static void viewport_interaction_remove_large_scenery(TileElement* tileElement,
 
     if (sceneryEntry->large_scenery.scrolling_mode != SCROLLING_MODE_NONE)
     {
-        BannerIndex bannerIndex = tileElement->AsLargeScenery()->GetBannerIndex();
+        auto bannerIndex = tileElement->AsLargeScenery()->GetBannerIndex();
         context_open_detail_window(WD_SIGN, bannerIndex);
     }
     else
diff --git a/src/openrct2-ui/windows/Sign.cpp b/src/openrct2-ui/windows/Sign.cpp
index 2a8b62b13e..8499a4aa8e 100644
--- a/src/openrct2-ui/windows/Sign.cpp
+++ b/src/openrct2-ui/windows/Sign.cpp
@@ -170,7 +170,7 @@ rct_window* window_sign_open(rct_windownumber number)
             rct_scenery_entry* scenery_entry = tile_element->AsLargeScenery()->GetEntry();
             if (scenery_entry != nullptr && scenery_entry->large_scenery.scrolling_mode != SCROLLING_MODE_NONE)
             {
-                BannerIndex bannerIndex = tile_element->AsLargeScenery()->GetBannerIndex();
+                auto bannerIndex = tile_element->AsLargeScenery()->GetBannerIndex();
 
                 if (bannerIndex == w->number)
                     break;
@@ -227,7 +227,7 @@ static void window_sign_mouseup(rct_window* w, rct_widgetindex widgetIndex)
                     rct_scenery_entry* scenery_entry = tile_element->AsLargeScenery()->GetEntry();
                     if (scenery_entry->large_scenery.scrolling_mode != SCROLLING_MODE_NONE)
                     {
-                        BannerIndex bannerIndex = tile_element->AsLargeScenery()->GetBannerIndex();
+                        auto bannerIndex = tile_element->AsLargeScenery()->GetBannerIndex();
                         if (bannerIndex == w->number)
                             break;
                     }
diff --git a/src/openrct2/actions/BannerSetStyleAction.hpp b/src/openrct2/actions/BannerSetStyleAction.hpp
index 9abba7f52e..9bcfcb0f06 100644
--- a/src/openrct2/actions/BannerSetStyleAction.hpp
+++ b/src/openrct2/actions/BannerSetStyleAction.hpp
@@ -29,7 +29,7 @@ DEFINE_GAME_ACTION(BannerSetStyleAction, GAME_COMMAND_SET_BANNER_STYLE, GameActi
 {
 private:
     uint8_t _type = static_cast<uint8_t>(BannerSetStyleType::Count);
-    uint8_t _bannerIndex = BANNER_INDEX_NULL;
+    BannerIndex _bannerIndex = BANNER_INDEX_NULL;
     uint8_t _parameter;
 
 public:
diff --git a/src/openrct2/actions/SignSetNameAction.hpp b/src/openrct2/actions/SignSetNameAction.hpp
index 06d24a7893..b87545226b 100644
--- a/src/openrct2/actions/SignSetNameAction.hpp
+++ b/src/openrct2/actions/SignSetNameAction.hpp
@@ -24,12 +24,12 @@
 DEFINE_GAME_ACTION(SignSetNameAction, GAME_COMMAND_SET_SIGN_NAME, GameActionResult)
 {
 private:
-    int32_t _bannerIndex;
+    BannerIndex _bannerIndex;
     std::string _name;
 
 public:
     SignSetNameAction() = default;
-    SignSetNameAction(int32_t bannerIndex, const std::string& name)
+    SignSetNameAction(BannerIndex bannerIndex, const std::string& name)
         : _bannerIndex(bannerIndex)
         , _name(name)
     {
@@ -48,7 +48,7 @@ public:
 
     GameActionResult::Ptr Query() const override
     {
-        if ((BannerIndex)_bannerIndex >= MAX_BANNERS || _bannerIndex < 0)
+        if (_bannerIndex >= MAX_BANNERS)
         {
             log_warning("Invalid game command for setting sign name, banner id = %d", _bannerIndex);
             return MakeResult(GA_ERROR::INVALID_PARAMETERS, STR_NONE);
diff --git a/src/openrct2/actions/SignSetStyleAction.hpp b/src/openrct2/actions/SignSetStyleAction.hpp
index d1d0ef3630..269b6f0153 100644
--- a/src/openrct2/actions/SignSetStyleAction.hpp
+++ b/src/openrct2/actions/SignSetStyleAction.hpp
@@ -23,14 +23,14 @@
 DEFINE_GAME_ACTION(SignSetStyleAction, GAME_COMMAND_SET_SIGN_STYLE, GameActionResult)
 {
 private:
-    int32_t _bannerIndex;
+    BannerIndex _bannerIndex;
     uint8_t _mainColour;
     uint8_t _textColour;
     bool _isLarge;
 
 public:
     SignSetStyleAction() = default;
-    SignSetStyleAction(int32_t bannerIndex, uint8_t mainColour, uint8_t textColour, bool isLarge)
+    SignSetStyleAction(BannerIndex bannerIndex, uint8_t mainColour, uint8_t textColour, bool isLarge)
         : _bannerIndex(bannerIndex)
         , _mainColour(mainColour)
         , _textColour(textColour)
@@ -51,7 +51,7 @@ public:
 
     GameActionResult::Ptr Query() const override
     {
-        if ((BannerIndex)_bannerIndex >= MAX_BANNERS || _bannerIndex < 0)
+        if (_bannerIndex >= MAX_BANNERS)
         {
             log_warning("Invalid game command for setting sign style, banner id '%d' out of range", _bannerIndex);
             return MakeResult(GA_ERROR::INVALID_PARAMETERS, STR_NONE);
@@ -63,7 +63,7 @@ public:
 
         if (_isLarge)
         {
-            TileElement* tileElement = banner_get_tile_element((BannerIndex)_bannerIndex);
+            TileElement* tileElement = banner_get_tile_element(_bannerIndex);
             if (tileElement == nullptr)
             {
                 log_warning("Invalid game command for setting sign style, banner id '%d' not found", _bannerIndex);
@@ -77,7 +77,7 @@ public:
         }
         else
         {
-            WallElement* wallElement = banner_get_scrolling_wall_tile_element(static_cast<BannerIndex>(_bannerIndex));
+            WallElement* wallElement = banner_get_scrolling_wall_tile_element(_bannerIndex);
 
             if (!wallElement)
             {
@@ -97,7 +97,7 @@ public:
 
         if (_isLarge)
         {
-            TileElement* tileElement = banner_get_tile_element((BannerIndex)_bannerIndex);
+            TileElement* tileElement = banner_get_tile_element(_bannerIndex);
             if (!map_large_scenery_sign_set_colour(
                     { coords, tileElement->GetBaseZ(), tileElement->GetDirection() },
                     tileElement->AsLargeScenery()->GetSequenceIndex(), _mainColour, _textColour))
@@ -107,7 +107,7 @@ public:
         }
         else
         {
-            WallElement* wallElement = banner_get_scrolling_wall_tile_element(static_cast<BannerIndex>(_bannerIndex));
+            WallElement* wallElement = banner_get_scrolling_wall_tile_element(_bannerIndex);
 
             wallElement->SetPrimaryColour(_mainColour);
             wallElement->SetSecondaryColour(_textColour);
@@ -115,7 +115,7 @@ public:
         }
 
         auto intent = Intent(INTENT_ACTION_UPDATE_BANNER);
-        intent.putExtra(INTENT_EXTRA_BANNER_INDEX, (BannerIndex)_bannerIndex);
+        intent.putExtra(INTENT_EXTRA_BANNER_INDEX, _bannerIndex);
         context_broadcast_intent(&intent);
 
         return MakeResult();
diff --git a/src/openrct2/common.h b/src/openrct2/common.h
index 1933e861cd..833ded0156 100644
--- a/src/openrct2/common.h
+++ b/src/openrct2/common.h
@@ -142,8 +142,6 @@ using money64 = fixed64_1dp;
 #define MONEY16_UNDEFINED (money16)(uint16_t) 0xFFFF
 #define MONEY32_UNDEFINED ((money32)0x80000000)
 
-using BannerIndex = uint8_t;
-
 using EMPTY_ARGS_VOID_POINTER = void();
 using rct_string_id = uint16_t;
 
diff --git a/src/openrct2/rct1/S4Importer.cpp b/src/openrct2/rct1/S4Importer.cpp
index 0019b816b0..f65540f1a1 100644
--- a/src/openrct2/rct1/S4Importer.cpp
+++ b/src/openrct2/rct1/S4Importer.cpp
@@ -2195,7 +2195,10 @@ private:
                 auto src2 = src->AsBanner();
 
                 uint8_t index = src2->GetIndex();
-                dst2->SetIndex(index);
+                if (index != RCT12_BANNER_INDEX_NULL)
+                    dst2->SetIndex(index);
+                else
+                    dst2->SetIndex(BANNER_INDEX_NULL);
                 dst2->SetPosition(src2->GetPosition());
                 dst2->SetAllowedEdges(src2->GetAllowedEdges());
 
diff --git a/src/openrct2/rct12/RCT12.cpp b/src/openrct2/rct12/RCT12.cpp
index da652ef7ab..0c0ae9b498 100644
--- a/src/openrct2/rct12/RCT12.cpp
+++ b/src/openrct2/rct12/RCT12.cpp
@@ -308,7 +308,7 @@ colour_t RCT12LargeSceneryElement::GetSecondaryColour() const
     return colour[1] & TILE_ELEMENT_COLOUR_MASK;
 }
 
-BannerIndex RCT12LargeSceneryElement::GetBannerIndex() const
+uint8_t RCT12LargeSceneryElement::GetBannerIndex() const
 {
     return (type & 0xC0) | (((colour[0]) & ~TILE_ELEMENT_COLOUR_MASK) >> 2) | (((colour[1]) & ~TILE_ELEMENT_COLOUR_MASK) >> 5);
 }
@@ -345,7 +345,7 @@ uint8_t RCT12WallElement::GetAnimationFrame() const
     return (animation >> 3) & 0xF;
 }
 
-BannerIndex RCT12WallElement::GetBannerIndex() const
+uint8_t RCT12WallElement::GetBannerIndex() const
 {
     return banner_index;
 }
@@ -413,7 +413,7 @@ uint8_t RCT12EntranceElement::GetPathType() const
     return pathType;
 }
 
-BannerIndex RCT12BannerElement::GetIndex() const
+uint8_t RCT12BannerElement::GetIndex() const
 {
     return index;
 }
@@ -480,19 +480,19 @@ uint8_t RCT12TileElement::GetBannerIndex()
         case TILE_ELEMENT_TYPE_LARGE_SCENERY:
             sceneryEntry = get_large_scenery_entry(AsLargeScenery()->GetEntryIndex());
             if (sceneryEntry->large_scenery.scrolling_mode == SCROLLING_MODE_NONE)
-                return BANNER_INDEX_NULL;
+                return RCT12_BANNER_INDEX_NULL;
 
             return AsLargeScenery()->GetBannerIndex();
         case TILE_ELEMENT_TYPE_WALL:
             sceneryEntry = get_wall_entry(AsWall()->GetEntryIndex());
             if (sceneryEntry == nullptr || sceneryEntry->wall.scrolling_mode == SCROLLING_MODE_NONE)
-                return BANNER_INDEX_NULL;
+                return RCT12_BANNER_INDEX_NULL;
 
             return AsWall()->GetBannerIndex();
         case TILE_ELEMENT_TYPE_BANNER:
             return AsBanner()->GetIndex();
         default:
-            return BANNER_INDEX_NULL;
+            return RCT12_BANNER_INDEX_NULL;
     }
 }
 
@@ -537,7 +537,7 @@ void RCT12LargeSceneryElement::SetSecondaryColour(colour_t newColour)
     colour[1] |= newColour;
 }
 
-void RCT12LargeSceneryElement::SetBannerIndex(BannerIndex newIndex)
+void RCT12LargeSceneryElement::SetBannerIndex(uint8_t newIndex)
 {
     type |= newIndex & 0xC0;
     colour[0] |= (newIndex & 0x38) << 2;
@@ -850,7 +850,7 @@ void RCT12WallElement::SetEntryIndex(uint8_t newIndex)
     entryIndex = newIndex;
 }
 
-void RCT12WallElement::SetBannerIndex(BannerIndex newIndex)
+void RCT12WallElement::SetBannerIndex(uint8_t newIndex)
 {
     banner_index = newIndex;
 }
@@ -929,7 +929,7 @@ void RCT12EntranceElement::SetStationIndex(uint8_t stationIndex)
     index |= (stationIndex << 4);
 }
 
-void RCT12BannerElement::SetIndex(BannerIndex newIndex)
+void RCT12BannerElement::SetIndex(uint8_t newIndex)
 {
     index = newIndex;
 }
diff --git a/src/openrct2/rct12/RCT12.h b/src/openrct2/rct12/RCT12.h
index 1ffde876ae..7c2f89c15f 100644
--- a/src/openrct2/rct12/RCT12.h
+++ b/src/openrct2/rct12/RCT12.h
@@ -48,6 +48,8 @@ constexpr uint16_t const RCT12_MAX_INVERSIONS = 31;
 constexpr uint16_t const RCT12_MAX_GOLF_HOLES = 31;
 constexpr uint16_t const RCT12_MAX_HELICES = 31;
 
+constexpr uint8_t RCT12_BANNER_INDEX_NULL = (uint8_t)-1;
+
 enum class RCT12TrackDesignVersion : uint8_t
 {
     TD4,
@@ -415,13 +417,13 @@ public:
     uint16_t GetSequenceIndex() const;
     colour_t GetPrimaryColour() const;
     colour_t GetSecondaryColour() const;
-    BannerIndex GetBannerIndex() const;
+    uint8_t GetBannerIndex() const;
 
     void SetEntryIndex(uint32_t newIndex);
     void SetSequenceIndex(uint16_t sequence);
     void SetPrimaryColour(colour_t colour);
     void SetSecondaryColour(colour_t colour);
-    void SetBannerIndex(BannerIndex newIndex);
+    void SetBannerIndex(uint8_t newIndex);
 };
 assert_struct_size(RCT12LargeSceneryElement, 8);
 struct RCT12WallElement : RCT12TileElementBase
@@ -430,8 +432,8 @@ private:
     uint8_t entryIndex; // 4
     union
     {
-        uint8_t colour_3;         // 5
-        BannerIndex banner_index; // 5
+        uint8_t colour_3;     // 5
+        uint8_t banner_index; // 5
     };
     uint8_t colour_1;  // 6 0b_2221_1111 2 = colour_2 (uses flags for rest of colour2), 1 = colour_1
     uint8_t animation; // 7 0b_dfff_ft00 d = direction, f = frame num, t = across track flag (not used)
@@ -442,7 +444,7 @@ public:
     colour_t GetSecondaryColour() const;
     colour_t GetTertiaryColour() const;
     uint8_t GetAnimationFrame() const;
-    BannerIndex GetBannerIndex() const;
+    uint8_t GetBannerIndex() const;
     bool IsAcrossTrack() const;
     bool AnimationIsBackwards() const;
     uint32_t GetRawRCT1WallTypeData() const;
@@ -455,7 +457,7 @@ public:
     void SetSecondaryColour(colour_t newColour);
     void SetTertiaryColour(colour_t newColour);
     void SetAnimationFrame(uint8_t frameNum);
-    void SetBannerIndex(BannerIndex newIndex);
+    void SetBannerIndex(uint8_t newIndex);
     void SetAcrossTrack(bool acrossTrack);
     void SetAnimationIsBackwards(bool isBackwards);
 };
@@ -484,19 +486,19 @@ assert_struct_size(RCT12EntranceElement, 8);
 struct RCT12BannerElement : RCT12TileElementBase
 {
 private:
-    BannerIndex index; // 4
-    uint8_t position;  // 5
-    uint8_t flags;     // 6
+    uint8_t index;    // 4
+    uint8_t position; // 5
+    uint8_t flags;    // 6
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wunused-private-field"
     uint8_t unused; // 7
 #pragma clang diagnostic pop
 public:
-    BannerIndex GetIndex() const;
+    uint8_t GetIndex() const;
     uint8_t GetPosition() const;
     uint8_t GetAllowedEdges() const;
 
-    void SetIndex(BannerIndex newIndex);
+    void SetIndex(uint8_t newIndex);
     void SetPosition(uint8_t newPosition);
     void SetAllowedEdges(uint8_t newEdges);
 };
diff --git a/src/openrct2/rct2/S6Exporter.cpp b/src/openrct2/rct2/S6Exporter.cpp
index 859dbb3616..29a75a4031 100644
--- a/src/openrct2/rct2/S6Exporter.cpp
+++ b/src/openrct2/rct2/S6Exporter.cpp
@@ -1521,9 +1521,15 @@ void S6Exporter::ExportTileElement(RCT12TileElement* dst, TileElement* src)
             dst2->SetSecondaryColour(src2->GetSecondaryColour());
             dst2->SetTertiaryColour(src2->GetTertiaryColour());
             dst2->SetAnimationFrame(src2->GetAnimationFrame());
-            dst2->SetBannerIndex(src2->GetBannerIndex());
             dst2->SetAcrossTrack(src2->IsAcrossTrack());
             dst2->SetAnimationIsBackwards(src2->AnimationIsBackwards());
+
+            auto bannerIndex = src2->GetBannerIndex();
+            if (bannerIndex != BANNER_INDEX_NULL)
+                dst2->SetBannerIndex(bannerIndex);
+            else
+                dst2->SetBannerIndex(RCT12_BANNER_INDEX_NULL);
+
             break;
         }
         case TILE_ELEMENT_TYPE_LARGE_SCENERY:
@@ -1535,7 +1541,13 @@ void S6Exporter::ExportTileElement(RCT12TileElement* dst, TileElement* src)
             dst2->SetSequenceIndex(src2->GetSequenceIndex());
             dst2->SetPrimaryColour(src2->GetPrimaryColour());
             dst2->SetSecondaryColour(src2->GetSecondaryColour());
-            dst2->SetBannerIndex(src2->GetBannerIndex());
+
+            auto bannerIndex = src2->GetBannerIndex();
+            if (bannerIndex != BANNER_INDEX_NULL)
+                dst2->SetBannerIndex(bannerIndex);
+            else
+                dst2->SetBannerIndex(RCT12_BANNER_INDEX_NULL);
+
             break;
         }
         case TILE_ELEMENT_TYPE_BANNER:
@@ -1543,9 +1555,13 @@ void S6Exporter::ExportTileElement(RCT12TileElement* dst, TileElement* src)
             auto dst2 = dst->AsBanner();
             auto src2 = src->AsBanner();
 
-            dst2->SetIndex(src2->GetIndex());
             dst2->SetPosition(src2->GetPosition());
             dst2->SetAllowedEdges(src2->GetAllowedEdges());
+            auto bannerIndex = src2->GetIndex();
+            if (bannerIndex != BANNER_INDEX_NULL)
+                dst2->SetIndex(bannerIndex);
+            else
+                dst2->SetIndex(RCT12_BANNER_INDEX_NULL);
             break;
         }
         default:
diff --git a/src/openrct2/scenario/Scenario.cpp b/src/openrct2/scenario/Scenario.cpp
index cc23b68021..f885144b23 100644
--- a/src/openrct2/scenario/Scenario.cpp
+++ b/src/openrct2/scenario/Scenario.cpp
@@ -651,8 +651,8 @@ void scenario_fix_ghosts(rct_s6_data* s6)
             {
                 if (originalElement->IsGhost())
                 {
-                    BannerIndex bannerIndex = originalElement->GetBannerIndex();
-                    if (bannerIndex != BANNER_INDEX_NULL)
+                    uint8_t bannerIndex = originalElement->GetBannerIndex();
+                    if (bannerIndex != RCT12_BANNER_INDEX_NULL)
                     {
                         auto banner = &s6->banners[bannerIndex];
                         if (banner->type != BANNER_NULL)
diff --git a/src/openrct2/world/Banner.cpp b/src/openrct2/world/Banner.cpp
index 8ef7b1c5c2..5045c40604 100644
--- a/src/openrct2/world/Banner.cpp
+++ b/src/openrct2/world/Banner.cpp
@@ -288,7 +288,7 @@ void fix_duplicated_banners()
                                 tileElement->base_height);
 
                             // Banner index is already in use by another banner, so duplicate it
-                            BannerIndex newBannerIndex = create_new_banner(GAME_COMMAND_FLAG_APPLY);
+                            auto newBannerIndex = create_new_banner(GAME_COMMAND_FLAG_APPLY);
                             if (newBannerIndex == BANNER_INDEX_NULL)
                             {
                                 log_error("Failed to create new banner.");
diff --git a/src/openrct2/world/Banner.h b/src/openrct2/world/Banner.h
index 750ee66390..d412636533 100644
--- a/src/openrct2/world/Banner.h
+++ b/src/openrct2/world/Banner.h
@@ -10,7 +10,13 @@
 #pragma once
 
 #include "../common.h"
-#include "TileElement.h"
+#include "../ride/RideTypes.h"
+#include "Location.hpp"
+
+struct TileElement;
+struct WallElement;
+
+typedef uint16_t BannerIndex;
 
 constexpr uint8_t BANNER_NULL = 255;
 constexpr size_t MAX_BANNERS = 250;
diff --git a/src/openrct2/world/TileElement.h b/src/openrct2/world/TileElement.h
index eadfa96894..9abc66e39f 100644
--- a/src/openrct2/world/TileElement.h
+++ b/src/openrct2/world/TileElement.h
@@ -11,6 +11,7 @@
 
 #include "../common.h"
 #include "../ride/RideTypes.h"
+#include "Banner.h"
 #include "Footpath.h"
 #include "Location.hpp"
 
@@ -389,9 +390,10 @@ struct LargeSceneryElement : TileElementBase
 {
 private:
     uint32_t EntryIndex;
-    uint32_t BannerIndex;
+    ::BannerIndex BannerIndex;
     uint8_t SequenceIndex;
     uint8_t Colour[3];
+    uint8_t pad[2];
 
 public:
     uint32_t GetEntryIndex() const;
@@ -426,7 +428,7 @@ private:
     uint8_t animation;        // 0A 0b_dfff_ft00 d = direction, f = frame num, t = across track flag (not used)
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wunused-private-field"
-    uint8_t pad_0B[5];
+    uint8_t pad_0C[4];
 #pragma clang diagnostic pop
 
 public:
@@ -502,7 +504,7 @@ private:
 #pragma clang diagnostic ignored "-Wunused-private-field"
     uint8_t flags;  // 6
     uint8_t unused; // 7
-    uint8_t pad_08[8];
+    uint8_t pad_09[7];
 #pragma clang diagnostic pop
 public:
     Banner* GetBanner() const;
diff --git a/src/openrct2/world/TileInspector.cpp b/src/openrct2/world/TileInspector.cpp
index c93ce36019..f6d9d44908 100644
--- a/src/openrct2/world/TileInspector.cpp
+++ b/src/openrct2/world/TileInspector.cpp
@@ -303,11 +303,11 @@ GameActionResult::Ptr tile_inspector_paste_element_at(CoordsXY loc, TileElement
     if (isExecuting)
     {
         // Check if the element to be pasted refers to a banner index
-        BannerIndex bannerIndex = tile_element_get_banner_index(&element);
+        auto bannerIndex = tile_element_get_banner_index(&element);
         if (bannerIndex != BANNER_INDEX_NULL)
         {
             // The element to be pasted refers to a banner index - make a copy of it
-            BannerIndex newBannerIndex = create_new_banner(GAME_COMMAND_FLAG_APPLY);
+            auto newBannerIndex = create_new_banner(GAME_COMMAND_FLAG_APPLY);
             if (newBannerIndex == BANNER_INDEX_NULL)
             {
                 return std::make_unique<GameActionResult>(GA_ERROR::UNKNOWN, STR_NONE);