diff --git a/datatypes/epc/domain/tests/test_from_site_notes.py b/datatypes/epc/domain/tests/test_from_site_notes.py
index 1c8c211cb..7a91425ea 100644
--- a/datatypes/epc/domain/tests/test_from_site_notes.py
+++ b/datatypes/epc/domain/tests/test_from_site_notes.py
@@ -777,6 +777,7 @@ class TestCylinderSizeCoding:
         "label, expected_code",
         [
             ("Normal (90-130 litres)", 2),
+            ("Medium (131-170 litres)", 3),  # Table 28 Medium → fixed 160 L
             ("Large (>170 litres)", 4),
             ("No Access", 2),  # fed from the (gas) main → Table 28 "otherwise"
         ],