diff --git a/packages/domain/src/domain/ml/tests/_fixtures.py b/packages/domain/src/domain/ml/tests/_fixtures.py
index bce05fda..ca4c906b 100644
--- a/packages/domain/src/domain/ml/tests/_fixtures.py
+++ b/packages/domain/src/domain/ml/tests/_fixtures.py
@@ -98,6 +98,7 @@ def make_sap_heating(
     cylinder_insulation_thickness_mm: Optional[int] = None,
     secondary_fuel_type: Optional[int] = None,
     secondary_heating_type: Optional[int] = None,
+    number_baths: Optional[int] = None,
 ) -> SapHeating:
     """Build a SapHeating with SAP10 API defaults."""
     return SapHeating(
@@ -112,6 +113,7 @@ def make_sap_heating(
         cylinder_insulation_thickness_mm=cylinder_insulation_thickness_mm,
         secondary_fuel_type=secondary_fuel_type,
         secondary_heating_type=secondary_heating_type,
+        number_baths=number_baths,
     )
 
 
diff --git a/packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_000477.py b/packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_000477.py
index f1e6db87..146b3972 100644
--- a/packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_000477.py
+++ b/packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_000477.py
@@ -26,7 +26,12 @@ from datatypes.epc.domain.epc_property_data import (
     SapVentilation,
     SapWindow,
 )
-from domain.ml.tests._fixtures import make_minimal_sap10_epc, make_window
+from domain.ml.tests._fixtures import (
+    make_main_heating_detail,
+    make_minimal_sap10_epc,
+    make_sap_heating,
+    make_window,
+)
 from domain.sap.worksheet.solar_gains import RoofWindowInput, RooflightInput
 from domain.sap.worksheet.ventilation import MechanicalVentilationKind
 from domain.sap.worksheet.water_heating import TABLE_J1_TCOLD_FROM_MAINS_C
@@ -76,6 +81,8 @@ def build_epc() -> EpcPropertyData:
         heated_rooms_count=4,
         door_count=2,
         percent_draughtproofed=100,
+        low_energy_fixed_lighting_bulbs_count=SECTION_5_BULB_COUNT_LEL,
+        sap_windows=list(SECTION_6_VERTICAL_WINDOWS),
         sap_ventilation=SapVentilation(
             extract_fans_count=2,
             sheltered_sides=2,
@@ -83,6 +90,16 @@ def build_epc() -> EpcPropertyData:
             suspended_timber_floor_sealed=False,
             has_draught_lobby=False,
         ),
+        sap_heating=make_sap_heating(
+            main_heating_details=[
+                make_main_heating_detail(
+                    main_heating_index_number=18118,
+                    main_heating_data_source=1,
+                ),
+            ],
+            secondary_heating_type=691,
+            number_baths=0,  # PDF: Total number of baths in property = 0
+        ),
     )
 
 
diff --git a/packages/domain/src/domain/sap/worksheet/tests/test_e2e_elmhurst_sap_score.py b/packages/domain/src/domain/sap/worksheet/tests/test_e2e_elmhurst_sap_score.py
index c184fa92..9748a66f 100644
--- a/packages/domain/src/domain/sap/worksheet/tests/test_e2e_elmhurst_sap_score.py
+++ b/packages/domain/src/domain/sap/worksheet/tests/test_e2e_elmhurst_sap_score.py
@@ -24,6 +24,7 @@ from domain.sap.calculator import Sap10Calculator
 from domain.sap.rdsap.cert_to_inputs import cert_to_inputs
 from domain.sap.worksheet.tests import (
     _elmhurst_worksheet_000474 as _w000474,
+    _elmhurst_worksheet_000477 as _w000477,
     _elmhurst_worksheet_000490 as _w000490,
 )
 from domain.sap.worksheet.tests._elmhurst_fixtures import (
@@ -53,6 +54,14 @@ _ELMHURST_000490_EXPECTED: Final[ElmhurstExpectedSap] = ElmhurstExpectedSap(
     total_energy_cost_gbp=807.5421,
     ecf=3.0539,
 )
+_ELMHURST_000477_EXPECTED: Final[ElmhurstExpectedSap] = ElmhurstExpectedSap(
+    sap_rating=65,
+    sap_score_continuous=65.0050,
+    space_heating_kwh=10111.2019,
+    hot_water_kwh=2116.0365,
+    total_energy_cost_gbp=732.1396,
+    ecf=2.5086,
+)
 _ELMHURST_000474_EXPECTED: Final[ElmhurstExpectedSap] = ElmhurstExpectedSap(
     sap_rating=62,
     sap_score_continuous=62.2584,
@@ -63,6 +72,44 @@ _ELMHURST_000474_EXPECTED: Final[ElmhurstExpectedSap] = ElmhurstExpectedSap(
 )
 
 
+@pytest.mark.xfail(
+    reason=(
+        "Table 3c two-profile combi-loss override not yet implemented. PCDB "
+        "18118 (Vaillant ecoTEC sustain 24) lodges separate_dhw_tests=2 → "
+        "spec routes to Table 3c, which uses both Profile M (F1, R1) and "
+        "Profile L (F2, R2) loss factors. Our override gate (`_pcdb_table_"
+        "3b_combi_loss_override`) only accepts separate_dhw_tests==1 (Table "
+        "3b row 1, single-profile) → falls back to Table 3a keep-hot time-"
+        "clock 600 kWh/yr default = 25x overshoot on combi loss → +712 HW "
+        "kWh → continuous SAP +0.83 over PDF (66 vs 65). Re-enable when "
+        "Table 3c lands per the next ticket (see project memory)."
+    ),
+    strict=True,
+)
+def test_elmhurst_000477_end_to_end_sap_score_matches_pdf() -> None:
+    """Cohort closure pin for 000477. Mid-terrace combi-gas with PCDF
+    Vaillant ecoTEC sustain 24 (index 18118) + Electricity Electric
+    Panel secondary heater (SAP code 691). PDF SAP rating 65."""
+    # Arrange
+    epc = _w000477.build_epc()
+
+    # Act
+    result = Sap10Calculator().calculate(epc)
+
+    # Assert — integer match (the rdsap engine integration gate).
+    delta = abs(result.sap_score - _ELMHURST_000477_EXPECTED.sap_rating)
+    assert delta == 0, (
+        f"SAP rating delta {delta} — expected 0 (integer match with PDF). "
+        f"Actual={result.sap_score}, expected={_ELMHURST_000477_EXPECTED.sap_rating}."
+    )
+    continuous_delta = abs(
+        result.sap_score_continuous - _ELMHURST_000477_EXPECTED.sap_score_continuous
+    )
+    assert continuous_delta <= 0.5, (
+        f"Continuous SAP delta {continuous_delta:.2f} exceeds ceiling 0.5"
+    )
+
+
 def test_elmhurst_000490_end_to_end_sap_score_currently_within_3_points() -> None:
     """Mid-terrace combi-gas dwelling with time-clock keep-hot. After the
     PCDB Table 105 integration the fixture lodges `main_heating_index_