diff --git a/infrastructure/hubspot/deal_properties_client.py b/infrastructure/hubspot/deal_properties_client.py
index d6f72b9e6..f97a51448 100644
--- a/infrastructure/hubspot/deal_properties_client.py
+++ b/infrastructure/hubspot/deal_properties_client.py
@@ -24,7 +24,13 @@ class HubspotDealPropertiesClient:
         a property whole (HubSpot has no append) would otherwise overwrite
         edits made since the last scrape.
         """
-        raise NotImplementedError
+        deal: Any = scrubbed_call_with_retry(
+            lambda: self._client.crm.deals.basic_api.get_by_id(  # type: ignore[reportUnknownMemberType]
+                deal_id, properties=[property_name]
+            )
+        )
+        properties = cast(Dict[str, Optional[str]], deal.properties)
+        return properties.get(property_name)
 
     def write_deal_property(
         self, deal_id: str, property_name: str, value: str
diff --git a/orchestration/abri_orchestrator.py b/orchestration/abri_orchestrator.py
index dfbf2dd80..c9fda15f5 100644
--- a/orchestration/abri_orchestrator.py
+++ b/orchestration/abri_orchestrator.py
@@ -270,7 +270,7 @@ class AbriOrchestrator:
             return tenancy
 
         if isinstance(tenancy, NoTenancyFound):
-            self._note_property_void(deal_id=deal_id, place_ref=place_ref)
+            self._note_property_void(deal_id=deal_id)
             return PropertyReportedVoid(place_ref=place_ref)
 
         contact_ids: List[str] = []
@@ -304,15 +304,30 @@ class AbriOrchestrator:
             ),
         )
 
-    def _note_property_void(self, deal_id: str, place_ref: PlaceRef) -> None:
-        """Record the void property in the deal's extra booking information.
+    def _note_property_void(self, deal_id: str) -> None:
+        """Flag the void property at the front of the deal's booking information.
 
-        Deliberately unimplemented: the extra-booking-information property is
-        not yet scraped onto the deal, so there is nothing to append to. The
-        write lands in the follow-up that adds the property; until then the
-        flow completes so a void property never dead-letters. Filling this in
-        is a single write_deal_property call with VOID_PROPERTY_NOTE.
+        HubSpot has no append, so the property is read and rewritten whole.
+        The read is live rather than from the scraped snapshot: the snapshot
+        lags by a scrape cycle, and rewriting from it would discard whatever a
+        coordinator typed in the meantime. The write is still last-write-wins
+        — HubSpot offers no compare-and-set — so the race is narrowed, not
+        closed.
         """
+        existing = (
+            self._deal_properties.read_deal_property(
+                deal_id=deal_id, property_name=NOTES_FOR_SURVEYOR_DEAL_PROPERTY
+            )
+            or ""
+        )
+        if existing.startswith(VOID_MARKER):
+            return
+
+        self._deal_properties.write_deal_property(
+            deal_id=deal_id,
+            property_name=NOTES_FOR_SURVEYOR_DEAL_PROPERTY,
+            value=f"{VOID_MARKER} {existing}".rstrip(),
+        )
 
     def amend_job(self, change: AppointmentChange) -> AmendJobOrchestrationResult:
         job_no = self._deal_database.job_no_for_deal(change.deal_id)