diff --git a/repositories/property/landlord_override_overlays.py b/repositories/property/landlord_override_overlays.py
index e987f7b26..21d9a8c1a 100644
--- a/repositories/property/landlord_override_overlays.py
+++ b/repositories/property/landlord_override_overlays.py
@@ -90,7 +90,15 @@ def overlays_from(overrides: ResolvedPropertyOverrides) -> list[EpcSimulation]:
         mapper = _COMPONENT_OVERLAYS.get(row.override_component)
         if mapper is None:
             continue
-        overlay = mapper(row.override_value, row.building_part)
+        value = row.override_value
+        if row.override_component == "main_heating_system":
+            # A fuel-agnostic gas-boiler archetype re-points to the oil / solid-fuel
+            # member matching this property's `main_fuel`, so an oil/solid boiler
+            # scores its own code — not the gas default the LLM assigned (ADR-0067).
+            value = resolve_boiler_archetype(
+                value, _override_value(overrides, "main_fuel")
+            )
+        overlay = mapper(value, row.building_part)
         if overlay is not None:
             overlays.append(overlay)
     return overlays