Hi can anyone help?

Is it possible to determine from the above what letter identified the
aircraft (eg MH F)?

Are other aircraft letters of Squadron 51 (flying from RAF Dishforth)
known so that this could be determined by a process of elimination?

My Grandfather was one of the pilots Sgt ESC Halsall lost in a
mission to Cologne on 01/03/1941~02/03/1941.

I think it is believed the MkV Whitley crashed in bad weather in the
North sea 50 miles from Newcastle, having requested a bearing at
about 1am and no crew survived.

Many thanks, Phil