Studying for the PPL exams
I strongly suggest that you get some banks of questions. The 'PPL Confuser' is possibly the most useful.
I read the books once through, then went through the question banks on the 'teach me to fly' CD (flightstore.co.uk), the 'Question and Answer Simplifier' (one of the set of books provided by the school) and the PPL Confuser (I got mine from Pooleys at Elstree) until I was hitting the mid 90 percent or better, then took each exam. If you can only find one of the above then get the PPL Confuser.
I got the Oxford Aviation CD as a supplement to the PPL books for metereology only, and found it very helpful for this subject. My wife used the radiotelephony disc, it is very good, for her R/T exam, but she is not a pilot and you will be getting lots of practice in the air.
Good luck!