If you haven't got your PPL then start with the Trevor Thom series. If you have, refresh your memory!
I think you can buy the Jeppesen/OAT set through the flight suppliers.
If you know with whom you wish to enrol, then have a chat with them and explain what you have told us - they may be able to help. Remeber, you have 18 months to pass the exams from the date of the first sitting but you can prepare for them in advance.
Hope this helps.
Cheers
Whirlygig