KH661
Mike,
The AirBritain serial numbers books show KH661 was delivered between September ’44 & January ’45 as a Mustang Mk 1V-it served with 442 Sqd RCAF & 19 Sqd RAF before being struck off charge on 18th February 1946. Airlife publications book Lend-Lease aircraft in WW11 by Arthur PEARCY shows KH661 as one of a batch of 30 P51Ds in contract AC-40063.These 30 aircraft carried RAF serials KH641-KH670 with US serials 44-11168-to 11187 & 44-11253 to 11262.
Hope this is some help.
Bigmal