Hello Malcolm
Have you tried the 97 Squadron Association?
I think you may need to look at all the 5 Group ORBs (which might confirm the name - no guarantee though). Although if it was a temporary appointment usually it is recorded, but no guarantee, or perhaps even check some files of No.5 Group and hope the name is printed, as this period is right on the changeover of the Air Officer Commanding No.5 Group AVM J C Slessor to AVM W A Coryton and may have had a Temporary AOC-in-C in between. A book on 5 Group researched from original records might mention the take-over from Slessor and any temporary AOC.
It appears from the leaving date of J C Slessor and the incoming date of the new 5 Group AOC there was a gap of several weeks in April 1942.
There was a G/Capt H A Haines but he was at another Group and I'm not really sure as the initials look like H. G., or if the whole word is a surname, his rank was Acting A/Cdre for a brief period from May 42 according to Malcolm Barrass 'Air of Authority'.
Also a Group SASO Senior Air Staff Officer standing in, might have signed.
The SASO appointed sometime in 1942 until 1944 was H V Satterly.
Sometimes you can find information by searching google with "FlightGlobal" with/without, his rank / AOC / AOC-in-C / "5 Group" or google with the beforementioned differing combinations in commas in the search bar, or names at
www.gazettes-online.co.uk
Mark