Major D.O Couper is missing, no doubt looking at the date the Schelde area but were would it be the best to look for information, I think: Piece reference DEFE 2/979 Combined Operations Headquaters: historical records, war diaries and record system organisation.
You'll have to forgive me..I get out of my depth when its after June 1940. I get the GSO 2 (General Staff Officer-Intelligence (IIRC)) bit but he must have been with a formation like 3 Division of XXX Corps etc? Edit Just looked him up on CWGC: CWGC :: Casualty Details
I would look in this one first: DEFE 2/31 Combined Operations Headquarters War Diaries 1944 Nov 1-1945 Jan 7