diff --git a/gateway-api/src/gateway_api/pds_search.py b/gateway-api/src/gateway_api/pds_search.py
index b21b6ecf..75abad86 100644
--- a/gateway-api/src/gateway_api/pds_search.py
+++ b/gateway-api/src/gateway_api/pds_search.py
@@ -138,19 +138,18 @@ def __init__(
 
     def _build_headers(
         self,
-        request_id: str | None = None,
         correlation_id: str | None = None,
     ) -> dict[str, str]:
         """
         Build mandatory and optional headers for a PDS request.
 
-        :param request_id: Optional ``X-Request-ID``. If not supplied a new UUID is
-                            generated.
+        A new UUID is generated for ``X-Request-ID`` with each call.
+
         :param correlation_id: Optional ``X-Correlation-ID`` for cross-system tracing.
         :return: Dictionary of HTTP headers for the outbound request.
         """
         headers = {
-            "X-Request-ID": request_id or str(uuid.uuid4()),
+            "X-Request-ID": str(uuid.uuid4()),
             "NHSD-End-User-Organisation-ODS": self.end_user_org_ods,
             "Accept": "application/fhir+json",
         }
@@ -173,7 +172,6 @@ def _build_headers(
     def search_patient_by_nhs_number(
         self,
         nhs_number: str,
-        request_id: str | None = None,
         correlation_id: str | None = None,
         timeout: int | None = None,
     ) -> PdsSearchResults | None:
@@ -183,9 +181,9 @@ def search_patient_by_nhs_number(
         Calls ``GET /Patient/{nhs_number}``, which returns a single FHIR Patient
         resource on success, then extracts a single :class:`PdsSearchResults`.
 
+        A new UUID is generated for the ``X-Request-ID`` header with each call.
+
         :param nhs_number: NHS number to search for.
-        :param request_id: Optional request ID to reuse for retries; if not supplied a
-            UUID is generated.
         :param correlation_id: Optional correlation ID for tracing.
         :param timeout: Optional per-call timeout in seconds. If not provided,
             :attr:`timeout` is used.
@@ -195,7 +193,6 @@ def search_patient_by_nhs_number(
             ``raise_for_status()`` raises :class:`requests.HTTPError`.
         """
         headers = self._build_headers(
-            request_id=request_id,
             correlation_id=correlation_id,
         )
 
diff --git a/gateway-api/src/gateway_api/test_pds_search.py b/gateway-api/src/gateway_api/test_pds_search.py
index a433c9a1..b0e98dd7 100644
--- a/gateway-api/src/gateway_api/test_pds_search.py
+++ b/gateway-api/src/gateway_api/test_pds_search.py
@@ -7,7 +7,6 @@
 from dataclasses import dataclass
 from datetime import date
 from typing import TYPE_CHECKING, Any, cast
-from uuid import uuid4
 
 import pytest
 import requests
@@ -270,7 +269,8 @@ def test_search_patient_by_nhs_number_sends_expected_headers(
     * Authorization header
     * NHSD-End-User-Organisation-ODS header
     * Accept header
-    * caller-provided X-Request-ID and X-Correlation-ID headers
+    * auto-generated X-Request-ID (UUID format)
+    * caller-provided X-Correlation-ID header
 
     :param stub: Stub backend fixture.
     :param mock_requests_get: Patched ``requests.get`` fixture capturing outbound
@@ -291,12 +291,10 @@ def test_search_patient_by_nhs_number_sends_expected_headers(
         base_url="https://example.test/personal-demographics/FHIR/R4",
     )
 
-    req_id = str(uuid4())
     corr_id = "corr-123"
 
     result = client.search_patient_by_nhs_number(
         "9000000009",
-        request_id=req_id,
         correlation_id=corr_id,
     )
     assert result is not None
@@ -305,7 +303,14 @@ def test_search_patient_by_nhs_number_sends_expected_headers(
     assert headers["Authorization"] == "Bearer test-token"
     assert headers["NHSD-End-User-Organisation-ODS"] == "A12345"
     assert headers["Accept"] == "application/fhir+json"
-    assert headers["X-Request-ID"] == req_id
+    # X-Request-ID should be auto-generated as a UUID
+    assert "X-Request-ID" in headers
+    assert isinstance(headers["X-Request-ID"], str)
+    assert len(headers["X-Request-ID"]) >= 32
+    # Verify it's a valid UUID by trying to parse it
+    from uuid import UUID
+
+    UUID(headers["X-Request-ID"])  # Should not raise
     assert headers["X-Correlation-ID"] == corr_id
 
 
@@ -314,10 +319,10 @@ def test_search_patient_by_nhs_number_generates_request_id(
     mock_requests_get: dict[str, Any],
 ) -> None:
     """
-    Verify that the client generates an X-Request-ID when not provided.
+    Verify that the client generates a new X-Request-ID for each request.
 
     The stub is in strict mode, so a missing or invalid X-Request-ID would cause a 400.
-    This test confirms a request ID is present and looks UUID-like.
+    This test confirms a request ID is present and is a valid UUID.
 
     :param stub: Stub backend fixture.
     :param mock_requests_get: Patched ``requests.get`` fixture capturing outbound