As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LHR INFLIGHT T100/01SEP - DURING APPROACH RECEIVED EICAS MESSAGE FOR SMOKE IN LAVATORY. LANDED WITHOUT INCIDENT. FOUND NO DAMAGE TO LAVATORIES AND NO EICAS MESSAGE PRESENT AND LAVATORY SMOKE DETECTORS PASSED TESTS. SYSTEM GROUND CHECKED NORMAL OPERATION.