I am fairly sure that Ronald Witts died in Scotland, there is 1 match on the Scottish register for that name in 1943, but I haven't got any credits for Scotlands People to check. From where he is buried I'd speculate a connection to the airfield at Perth.
There are 3 people with the name Donald McColl in Scotland, and as he was from Glasgow and is buried in Glasgow I'd say he is one of those 3.
There isn't anyone by the name of Bertram Osborne in Scotland or the Isle of Man so possibly Northern Ireland.
Peak District Air Accident Research