diff --git a/src/openrct2-ui/windows/Sign.cpp b/src/openrct2-ui/windows/Sign.cpp
index 1671a0b459..1554c83416 100644
--- a/src/openrct2-ui/windows/Sign.cpp
+++ b/src/openrct2-ui/windows/Sign.cpp
@@ -59,9 +59,14 @@ class SignWindow final : public Window
 private:
     bool _isSmall = false;
 
+    BannerIndex GetBannerIndex() const
+    {
+        return BannerIndex::FromUnderlying(number);
+    }
+
     void ShowTextInput()
     {
-        auto* banner = GetBanner(BannerIndex::FromUnderlying(number));
+        auto* banner = GetBanner(GetBannerIndex());
         if (banner != nullptr)
         {
             auto bannerText = banner->GetText();
@@ -87,14 +92,14 @@ public:
     {
         number = windowNumber;
         _isSmall = isSmall;
-        auto* banner = GetBanner(BannerIndex::FromUnderlying(number));
+        auto* banner = GetBanner(GetBannerIndex());
         if (banner == nullptr)
         {
             return false;
         }
 
         auto signViewPosition = banner->position.ToCoordsXY().ToTileCentre();
-        auto* tileElement = banner_get_tile_element(BannerIndex::FromUnderlying(number));
+        auto* tileElement = banner_get_tile_element(GetBannerIndex());
         if (tileElement == nullptr)
             return false;
 
@@ -138,7 +143,7 @@ public:
 
     void OnMouseUp(rct_widgetindex widgetIndex) override
     {
-        auto* banner = GetBanner(BannerIndex::FromUnderlying(number));
+        auto* banner = GetBanner(GetBannerIndex());
         if (banner == nullptr)
         {
             Close();
@@ -151,7 +156,7 @@ public:
                 break;
             case WIDX_SIGN_DEMOLISH:
             {
-                auto* tileElement = banner_get_tile_element(BannerIndex::FromUnderlying(number));
+                auto* tileElement = banner_get_tile_element(GetBannerIndex());
                 if (tileElement == nullptr)
                 {
                     Close();
@@ -203,8 +208,7 @@ public:
                 if (dropdownIndex == -1)
                     return;
                 list_information_type = dropdownIndex;
-                auto signSetStyleAction = SignSetStyleAction(
-                    BannerIndex::FromUnderlying(number), dropdownIndex, var_492, !_isSmall);
+                auto signSetStyleAction = SignSetStyleAction(GetBannerIndex(), dropdownIndex, var_492, !_isSmall);
                 GameActions::Execute(&signSetStyleAction);
                 break;
             }
@@ -213,8 +217,7 @@ public:
                 if (dropdownIndex == -1)
                     return;
                 var_492 = dropdownIndex;
-                auto signSetStyleAction = SignSetStyleAction(
-                    BannerIndex::FromUnderlying(number), list_information_type, dropdownIndex, !_isSmall);
+                auto signSetStyleAction = SignSetStyleAction(GetBannerIndex(), list_information_type, dropdownIndex, !_isSmall);
                 GameActions::Execute(&signSetStyleAction);
                 break;
             }
@@ -229,7 +232,7 @@ public:
     {
         if (widgetIndex == WIDX_SIGN_TEXT && !text.empty())
         {
-            auto signSetNameAction = SignSetNameAction(BannerIndex::FromUnderlying(number), std::string(text));
+            auto signSetNameAction = SignSetNameAction(GetBannerIndex(), std::string(text));
             GameActions::Execute(&signSetNameAction);
         }
     }
@@ -290,7 +293,7 @@ public:
     {
         RemoveViewport();
 
-        auto banner = GetBanner(BannerIndex::FromUnderlying(number));
+        auto banner = GetBanner(GetBannerIndex());
         if (banner == nullptr)
         {
             return;