Viv,
I'll add a bit more about James Alfred MASON, although he comes under the "Unaccounted for" category in RAF terms. At the time of his death he was serving at RAF Aston Down (formerly RAF Minchinhampton during WW1) in Gloucestershire with 55 Operational Training Unit and flying a Typhoon 1b serial number JP433. His service record and flying logbook are, like all of those relating to WW2, still with the RAF and have not yet been released to the National Archives.
During the two years previous to his death on 20 March 1945, JP433 had been involved in several crashes with other pilots and had been patched up, but I fear we are not going to get information about the circumstances of his death until the records are released for public consumption.
Maurice