diff --git a/src/eligibility_signposting_api/common/request_validator.py b/src/eligibility_signposting_api/common/request_validator.py
index cd213287a..e4fe7ab76 100644
--- a/src/eligibility_signposting_api/common/request_validator.py
+++ b/src/eligibility_signposting_api/common/request_validator.py
@@ -42,10 +42,14 @@ def validate_query_params(query_params: dict[str, str]) -> tuple[bool, ResponseR
 def validate_nhs_number(path_nhs: str | None, header_nhs: str | None) -> bool:
     logger.info("NHS numbers from the request", extra={"header_nhs": header_nhs, "path_nhs": path_nhs})
 
-    if not header_nhs or not path_nhs:
-        logger.error("NHS number is not present", extra={"header_nhs": header_nhs, "path_nhs": path_nhs})
+    if not path_nhs:
+        logger.error("NHS number is not present in path", extra={"path_nhs": path_nhs})
         return False
 
+    if not header_nhs:  # Not a validation error
+        logger.info("NHS number is not present in header", extra={"header_nhs": header_nhs, "path_nhs": path_nhs})
+        return True
+
     if header_nhs != path_nhs:
         logger.error("NHS number mismatch", extra={"header_nhs": header_nhs, "path_nhs": path_nhs})
         return False
diff --git a/tests/unit/common/test_request_validator.py b/tests/unit/common/test_request_validator.py
index 7de1c776a..e04392ebd 100644
--- a/tests/unit/common/test_request_validator.py
+++ b/tests/unit/common/test_request_validator.py
@@ -20,9 +20,9 @@ class TestValidateNHSNumber:
     @pytest.mark.parametrize(
         ("path_nhs", "header_nhs", "expected_result", "expected_log_msg"),
         [
-            (None, None, False, "NHS number is not present"),
-            ("1234567890", None, False, "NHS number is not present"),
-            (None, "1234567890", False, "NHS number is not present"),
+            (None, None, False, "NHS number is not present in path"),
+            ("1234567890", None, True, None),
+            (None, "1234567890", False, "NHS number is not present in path"),
             ("1234567890", "0987654321", False, "NHS number mismatch"),
             ("1234567890", "1234567890", True, None),
         ],