The design of the engine is Grob's modification (bore-out to 2500cc) of Porche's 4 pot Boxer.
Can't see where clubs would be saving engine hours by using them as SLG, There's a lot better performing "turbo" gliders on the market.
All the clubs I've visited use them for field landing checks, Comp "spotting" and as a cheap alternative to a light aircraft for touring/general handling. The glide ratio 28-30/1 isn't brilliant, but perfectly adequate for the jobs described above.
If the ACO did decide to re-engine with rotax 912's then they could add hooks and bring aerotowing capability back to the ATC.
The RAF does have a limited capability for light aircraft/glider support. The half dozen or so guys at Halton who run the RAFGSA centre, are all serving, or LEC, qualified on pistons/GRP/light airframe repair and did completely re-build three Pawnees (one of which is now part of the Glider-FX display team), whilst also keeping the GSA centre fleet and the Chip(super)munk fleet in the air.