I have enrolled with Egnatia (EG), recieved my PPL study pack and can confirm that the PPL part of the ATPL course is self study and that EG provide a full study pack with all the necassary material in order to study the theory involved. The PPL books I was provided with are AFE guides which are very good and partially colour printed with good diagrams and tables.
The PPL pack also includes a headset for you to keep, Pooly's CRP-5, a flight rule, protractor and a 1:500,000 area chart. All the stuff is neatly put place in a flight bag which is also provided. I hav yet to recieve my headset and uniform and will collect it once i start in June so most likely the same will apply to yourself.
As far as I am aware, no further costs are involved. However, if you do require further instruction or help by an EG instructor towards the PPL theory then you would need to pay a per/hr rate which I am not aware of.
The CATS guide that you are talking about are not needed until the JAR-ATPL groundschool and is included in the 0-to-fATPL package.
Hope that helps and see you soon,
M.H.Ali