Fred,
Trust me. You need nothing more than the Thom books (1,2,3,4), CAP413, Human Factors for Pilots (ISBN 0-291-39827-8) and the PPL Confuser. The multimedia stuff will add nothing. The instrument stuff will just confuse the situation.
That list will get 90%+ passes on all subjects so long as you read everything fully and test yourself with the Confuser.
The little Maycom Scanner is worth a purchase too. But don't let real-life R/T corrupt your ability to pass the R/T exams. Only verbatim CAP413 recall will be of assistance there!
Good luck!