diff --git a/backend/condition/lookups/uprn_lookup.py b/backend/condition/lookups/uprn_lookup.py
index b817445d..0f6e78fd 100644
--- a/backend/condition/lookups/uprn_lookup.py
+++ b/backend/condition/lookups/uprn_lookup.py
@@ -3,7 +3,6 @@ from typing import BinaryIO, Dict
 
 
 class UprnLookup(ABC):
-    def get_location_ref_to_uprn_map(
-        self, lookup_file_stream: BinaryIO
-    ) -> Dict[str, int]:
+    @abstractmethod
+    def get_property_ref_to_uprn_lookup(self) -> Dict[str, int]:
         pass
diff --git a/backend/condition/lookups/uprn_lookup_csv.py b/backend/condition/lookups/uprn_lookup_csv.py
index 43544ccd..8b1c21a2 100644
--- a/backend/condition/lookups/uprn_lookup_csv.py
+++ b/backend/condition/lookups/uprn_lookup_csv.py
@@ -4,21 +4,20 @@ from typing import BinaryIO, Dict, TextIO
 from backend.condition.lookups.uprn_lookup import UprnLookup
 
 
-class UprnLookupCsv(UprnLookup):
-    def get_location_ref_to_uprn_map(
-        self, lookup_file_stream: BinaryIO
-    ) -> Dict[str, int]:
-        text_stream: TextIO = TextIOWrapper(lookup_file_stream, encoding="utf-8")
-        location_ref_to_uprn_map: Dict[str, int] = {}
+class UprnLookupLocal(UprnLookup):
+    def __init__(self, csv_path: str):
+        self.csv_path = csv_path
 
+    def get_property_ref_to_uprn_lookup(self) -> Dict[str, int]:
+        with open(self.csv_path, "rb") as f:
+            return self.parse_csv(f)
+
+    def parse_csv(self, file_stream: BinaryIO) -> Dict[str, int]:
+        text_stream: TextIO = TextIOWrapper(file_stream, encoding="utf-8")
+        mapping: Dict[str, int] = {}
         reader = csv.DictReader(text_stream)
         for row in reader:
             if not row["reference"] or not row["out_uprn"]:
-                # skip empty rows
                 continue
-
-            ref = row["reference"].strip()
-            uprn = int(row["out_uprn"].strip())
-            location_ref_to_uprn_map[ref] = uprn
-
-        return location_ref_to_uprn_map
+            mapping[row["reference"].strip()] = int(row["out_uprn"].strip())
+        return mapping
diff --git a/backend/condition/lookups/uprn_lookup_s3.py b/backend/condition/lookups/uprn_lookup_s3.py
new file mode 100644
index 00000000..1eb68aae
--- /dev/null
+++ b/backend/condition/lookups/uprn_lookup_s3.py
@@ -0,0 +1,23 @@
+import csv
+from io import TextIOWrapper
+from typing import BinaryIO, Dict, TextIO
+from backend.condition.lookups.uprn_lookup import UprnLookup
+
+
+class UprnLookupS3(UprnLookup):
+    def __init__(self, bucket: str = "", key: str = ""):
+        self.bucket = bucket
+        self.key = key
+
+    def get_property_ref_to_uprn_lookup(self) -> Dict[str, int]:
+        raise NotImplementedError()
+
+    def _parse_csv(self, file_stream: BinaryIO) -> Dict[str, int]:
+        text_stream: TextIO = TextIOWrapper(file_stream, encoding="utf-8")
+        mapping: Dict[str, int] = {}
+        reader = csv.DictReader(text_stream)
+        for row in reader:
+            if not row["reference"] or not row["out_uprn"]:
+                continue
+            mapping[row["reference"].strip()] = int(row["out_uprn"].strip())
+        return mapping
diff --git a/backend/condition/tests/lookups/test_uprn_lookup_csv.py b/backend/condition/tests/lookups/test_uprn_lookup_csv.py
index a2d66a94..d01c52c2 100644
--- a/backend/condition/tests/lookups/test_uprn_lookup_csv.py
+++ b/backend/condition/tests/lookups/test_uprn_lookup_csv.py
@@ -1,23 +1,26 @@
-from typing import Any, Dict
 import pytest
-from io import BytesIO
+from typing import Dict
+from tempfile import NamedTemporaryFile
 
-from backend.condition.lookups.uprn_lookup_csv import UprnLookupCsv
+from backend.condition.lookups.uprn_lookup_csv import UprnLookupLocal
 
 
 @pytest.fixture
-def prop_ref_uprn_csv_bytes() -> BytesIO:
-    csv_bytes = b"""reference,out_uprn
+def prop_ref_uprn_csv_file() -> str:
+    csv_content = """reference,out_uprn
     ABC123,10000000001
     DEF456,10000000002
     GHI789,10000000003
     """
-    return BytesIO(csv_bytes)
+    with NamedTemporaryFile(mode="w+", delete=False, suffix=".csv") as tmp:
+        tmp.write(csv_content)
+        tmp.flush()
+        return tmp.name
 
 
-def test_generate_prop_ref_uprn_from_csv_bytes(prop_ref_uprn_csv_bytes) -> None:
+def test_generate_prop_ref_uprn_from_csv_file(prop_ref_uprn_csv_file: str) -> None:
     # arrange
-    uprn_lookup = UprnLookupCsv()
+    uprn_lookup = UprnLookupLocal(prop_ref_uprn_csv_file)
     expected_map: Dict[str, int] = {
         "ABC123": 10000000001,
         "DEF456": 10000000002,
@@ -25,9 +28,7 @@ def test_generate_prop_ref_uprn_from_csv_bytes(prop_ref_uprn_csv_bytes) -> None:
     }
 
     # act
-    actual_map: Dict[str, int] = uprn_lookup.get_location_ref_to_uprn_map(
-        prop_ref_uprn_csv_bytes
-    )
+    actual_map: Dict[str, int] = uprn_lookup.get_property_ref_to_uprn_lookup()
 
     # assert
     assert actual_map == expected_map