Likewise, I'm out of date and out of touch, so don't take this as gospel, but
In addition to this...
I'm not sure if you can count instructional hours towards PPL issue as most VGS instructors (probably) don't have TMG instructor ratings.
...would not the flying have to be within a correctly authorised civilian flying school as well in order to count??
The Air Cadet Pilot Scheme (at Tayside) counts towards a PPL as it ticks both boxes...not sure any other form of Air Cadet flying does (but note the disclaimer above).