diff --git a/repositories/property/landlord_override_overlays.py b/repositories/property/landlord_override_overlays.py
index b65cf5d29..7477cc785 100644
--- a/repositories/property/landlord_override_overlays.py
+++ b/repositories/property/landlord_override_overlays.py
@@ -67,9 +67,22 @@ _COMPONENT_OVERLAYS: dict[str, Callable[[str, int], Optional[EpcSimulation]]] =
 }
 
 
+# Components whose overlay must be applied LAST so an explicit value wins a
+# default another overlay dragged. `apply_simulations` is last-wins and override
+# rows arrive in arbitrary order, so a `main_fuel` override must be applied after
+# the `main_heating_system` archetype, whose natural-fuel default it overrides
+# (ADR-0041) — e.g. "smokeless coal" must beat a solid-fuel room heater's coal
+# default.
+_APPLY_LAST: frozenset[str] = frozenset({"main_fuel"})
+
+
 def overlays_from(overrides: ResolvedPropertyOverrides) -> list[EpcSimulation]:
     overlays: list[EpcSimulation] = []
-    for row in overrides.rows:
+    # Stable sort: non-`_APPLY_LAST` rows keep their order, `main_fuel` goes last.
+    ordered_rows = sorted(
+        overrides.rows, key=lambda row: row.override_component in _APPLY_LAST
+    )
+    for row in ordered_rows:
         mapper = _COMPONENT_OVERLAYS.get(row.override_component)
         if mapper is None:
             continue