RAOC Malta

My father-in-law Fred Watts was posted to Malta in 1941 (59th section) and served there throughout the war until 1945 by which time he was WOII. Some time during that period he was awarded the BEM for bravery. I would very much like to try to find out more. Were War Diaries kept? Where would any RAOC records for that time be held? Greatly appreciate any help.
PS. He returned to malta on holiday in the 1970s and visited Victoria Barracks, where he found his Maltese assistant's name still on the office door and his (Fred's) wartime calendar picture still on the office wall!