diff --git a/backend/pashub_fetcher/core_files.py b/backend/pashub_fetcher/core_files.py
index aa426475..b5ce1073 100644
--- a/backend/pashub_fetcher/core_files.py
+++ b/backend/pashub_fetcher/core_files.py
@@ -39,4 +39,14 @@ def infer_file_type(filename: str) -> Optional[str]:
     for core_file, file_type in CORE_TO_FILETYPE_MAP.items():
         if filename.startswith(core_file.value):
             return file_type
+
+    if CoreFiles.IMPROVEMENT_OPTION_EVALUATION.value in filename:
+        return CORE_TO_FILETYPE_MAP[CoreFiles.IMPROVEMENT_OPTION_EVALUATION]
+
+    if CoreFiles.MEDIUM_TERM_IMPROVEMENT_PLAN.value in filename:
+        return CORE_TO_FILETYPE_MAP[CoreFiles.MEDIUM_TERM_IMPROVEMENT_PLAN]
+
+    if "-OSM-" in filename and "DR-N-A" in filename:
+        return CORE_TO_FILETYPE_MAP[CoreFiles.RETROFIT_DESIGN_DOC]
+
     return None
diff --git a/backend/pashub_fetcher/tests/test_core_files.py b/backend/pashub_fetcher/tests/test_core_files.py
index fca29b7e..f8e8b431 100644
--- a/backend/pashub_fetcher/tests/test_core_files.py
+++ b/backend/pashub_fetcher/tests/test_core_files.py
@@ -1,5 +1,3 @@
-import pytest
-
 from backend.pashub_fetcher.core_files import infer_file_type
 
 
@@ -59,6 +57,6 @@ def test_infer_medium_term_improvement_plan():
     assert infer_file_type("60800802 - NG4 4HD - Medium Term Improvement Plan IOE.pdf") == "medium_term_improvement_plan"
 
 
-@pytest.mark.skip(reason="Retrofit Design Doc filename pattern not yet known")
 def test_infer_retrofit_design_doc():
-    assert infer_file_type("2512-OSM-H56M900-XX-DR-N-A_Radford Road 408.pdf") == "retrofit_design_doc"
+    assert infer_file_type("2512-OSM-H21M900-XX-DR-N-A_Lord Nelson Street 018.pdf") == "retrofit_design_doc"
+    assert infer_file_type("2603-OSM-B06M901-XX-DR-N-A_Alvaston Walk 022.pdf") == "retrofit_design_doc"