Can I recommend The Gliding Centre at Husbands Bosworth? Large airfield (possibly the longest unlicensed grass runway in UK), 7 day operation, professionally run courses during the season. Good club fleet of K21, Puchacz and Duo Discus 2 seat gliders for training plus a modern Rotax Falke motorglider. There are also a lot of privately owned and operated powered aircraft based on site so plenty of interest for a PPL pilot! I'm sure you'll appreciate being aerotowed to 4000ft behind a DHC-1 Chipmunk and then watching it dive away once you have released from tow (the club has 3 for tugs). Finally, the club is easily accessed from the M1/M6 motorways and has on site accommodation in private rooms and on-site catering.