RAF WWII locations tended to be Stations, Bases, Centres, and Depots. I don't think the RAF used Camp as a location (though possibly the Army did). I think that this Airmen's Rest Camp was simply the proud creation of OC No1 Personnel Base Depot and no doubt maintained his Airmen's morale as indicated in the Unit Diary you illustrated.
Talking of morale, much the same can be said of the 'story' and picture of an RAF Sgt Pilot and his Giant Mushroom. This was straight out of the RAF
PR Department, who probably provided the mushroom as well! It got the RAF into the newspapers, promoting both it and civilian morale. It also shows a volunteer from the Empire who has answered the call to arms. Tick! Tick! What it tells us is that at that date this was a fully qualified RAF pilot, witness Wings and Sergeant's Chevrons. If he was at an EFTS then he must have been an instructor there (unless of course his tunic was also part of the props, along with the mushroom). I rather doubt that. There were hundreds of thousands of fully qualified RAF pilots, why invent one?
If he started the war as a fully qualified RAFVR pilot, as suggested by Ron, would that account for it? Would he still have to go through basic training as an AC2/LAC? Don't know, Danny would have!