Hi, I am in a similar position to you. I have the OAT PPL package and it is very informative however I have been assured that the content is far too detailed for any PPL theory examination. I have also bought the PRATT books which again are very interesting and well written but my favourite media package is one provided by CATS which seems far easier to digest. I also like the test feature. You can access a demo from the homepage.
http://www.cranfieldaviation.com/uk/index.html
Please note that I have not subscribed to the CATS course, as I have all the other books and CD roms and really must save my hard earned cash for flying. The demo looks pretty good though.
Enjoy!