The VGS system is not the equivalent of an AOC operation; it is the equivalent to a 'corporate flight department' i.e. a private operation providing free flights to non-employees. The civil equivalent would be a pilot training organisation, which at the glider level, equates to the present BGA club system, albeit with cadets still not paying for their flights in the same way that BGA trainees do.
However since the RAF own the train-set, they could insist on whatever civilian equivalent type of organisation and pilot licence requirements that they think suitable for the level of risk they assign to the work.
Flug