Unfortunately not my friend. Many moon's ago when it was still the old CAA PPL you could credit some gliding time towards gaining your PPL, I think 5 hours in total was allowed. Nowaday's with JAR on the go I believe that things have changed. You can certainly credit gliding hours towards PPL but unfortunately you need to have a silver C qualification in gliding first before you can do it. You can also credit gliding hours towards your CPL but again there's only a maximum number you can use and of course you need a PPL first before you go for a PPL. If i'm wrong then apologies but that's certainly my unerstanding of things at the mo. I had over a hundred gliding hours when I finally went for my PPL and the CAA only let me credit 5 of them. Hope this hasnt confused you?? If your ever in any doubt then phone the CAA, they should be able to give you an answer over the phone,
Not off the top of my head but they're on the web somewhere. Is it not www.caa.org.co.uk or something similar?? You should find loads of contact numbers there.