Just one small point on the books and such. Nav, met, principles of flight don't really go out of date. Air law does, so buy this one new, latest edition.
For some really good stuff FREE google Pelican's Perch. Consider finding some information by yourself as a useful exercise that will save long term reliance on Pprune, helpful though the members are. There are still public libraries in UK, feel free to study there as well if you have problems finding a quiet time at home. You can dowload stuff from t'internet to a mobile device as well, instapaper is useful to get just the info (text and drawings) without the arty web page stuff, and you can then read on your kindle or ipad or whatever offline.
It is Ok to have more knowledge than the minimum required for the test, but try not to get bogged down in the minute detail on stuff like well, air law. Extra knowledge on met however may one day save you getting badly scared.
What I am trying to say is organise your priorities sensibly, study at home, and use that valuable resource known as a flying instructor. Many of the people here are instructors but you will also get less knowledgeable people posting. Use common sense when sorting out the information you get.
Oh, and did anyone mention not to pay up front?