Service records of Officers that served from 1922 onwards and Airmen that served from 1924 onwards are held at Personnel Management Agency (PMA).Please write to:
PMA(Sec)1b
Building 248A
RAF Innsworth
Gloucester
GL3 1EZ
The above is taken from:
The Veterans' Agency
As NoK your aunt can get service records from PMA for free (I believe) or you can pay to get them on her behalf. The original report of the loss of the aircraft will be held with the Air Historical Branch at Old Scotland Yard, London.
I know that
Ian Allan
have bomber and fighter command losses that have been published are were planning the coastal version.
5,863 aircrew of Coastal Command gave their lives during WWII, we should not forget their supreme sacrifice.
Best of luck, hope this in some way helps.