Guys,
Distance learning for ATPL's must include 650 hours of study of which at least 10% must be classroom based with your distance learning provider.
The proof of your 650 hours study is generally through completion of progress tests with a particular provider, so don't expect to do your own study, sign up with a registered school one day and do the exams the next.
The schools have to authorise and submit your exam application and as your results affect their pass rates, you can be damn sure they won't put you in for the exams until you have shown them you won't screw up.
Likewise the distance learning schools will provide you with notes/books from which to study, so don't go buying lots of expensive books only to find you receive a shiny new set when you sign up for the course! Depending on the books that would waste £500-£650 if you bought them new.
The best and cheapest start IMHO is to re-learn your PPL stuff as you will be surprised just how much airlaw, met etc. you have forgotten. If you can get hold of some cheap used ATPL notes then fine, but without an organised study plan (another useful part provided by the training provider), the sheer volume and complexity can seem overwhelming, hence my suggestion above.
Regards,
Obs