...why would you need forty degrees of flap at say EGNX, that might just just delay vacation of the active runway.
Fly the aeroplane, not the aerodrome.
Regarding solo stalling, I say with forty degrees of flap, I would not be happy with allowing that, unless the student was well trained in spin recovery.
The student should be taught to recover at the first indication of stall warning in that configuration, rather than waiting for the stall identification and fully developed stage. They should certainly practise stalling in the approach configuration solo, recovering at the incipient stage.
it would be interesting to know what the RAF CFS rules are on solo flight on the Grob 115 during initial trainingg.
I don't know what the RAF policy is with the plastic pig, but certainly all UAS Bulldog students were required to practise stalling, steep turns and PFLs solo. Plus aerobatics once they'd been taught them and had passed their spin/aeros check. Just as I did back in Chipmunk days - and during my original PPL course on the Cessna 150 (but not the aeros!).