As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LHR - CREW REPORTED PRIOR TO LANDING VERY STRONG ELECTRICAL BURNING SMELL ON RIGHT SIDE OF FIRST CLASS CABIN. RECIRCULATION FANS, IN-FLIGHT ENTERTAINMENT AND GALLEY OVENS TURNED OFF. SMOKE AND SMELL QUICKLY DISSIPATED. FLIGHT LANDED LHR WITHOUT INCIDENT. REPLACED AUDIO VIDEO UNIT. SYSTEM GROUND CHECK NORMAL OPERATION.