"Blackie" & "Kirk"

[DasKapitalist]

There is a picture on p. 62 of Martin Bowman's "Mosquito Fighter/Fighter-Bomber Units of World War 2" (Osprey Combat Aircraft #9) which shows Squadron Leader David J. 'Blackie' Williams DFC and his navigator, Flight Officer C.J. ‘Kirk’ Kirkpatrick and their 406 (Lynx) Squadron Mosquito aptly named “Blackie†& “Kirkâ€Â.

I believe this aircraft may have been the one used during the night of 29/30th April 1944 when they destroyed two Do217K-2s of KG100 attempting to attack the battleship HMS Howe while docked in Devonport with Fritz-X guided bombs.

According to “Aces High†by Christopher Shores and Clive Williams their aircraft was a Mosquito NF Mk.XII was coded “HU-Oâ€Â. However, Andrew Thomas, in his excellent "Mosquito Aces of World War 2", maintains that this aircraft was coded "HU-D" and was subsequently used by Wing Commander Robert C. Fumerton on the night of 14/15th May 1944 to score his 14th and final kill of the war.

Does anyone have any thoughts regarding the code letter issue or any leads regarding the serial of the Mosquito (possibly one of the following candidates: HK137; HK138; HK164 “Nâ€Â; HK179; HK180 “Aâ€Â; HK223; HK228; and HK231)?