glad to see this option is still available in the uk - correct me if i'm wrong, but the option 'do-it-yourself-theoretical-ATPL' doesn't exist anymore in the JAA-countries - as you have to pass through approved FTO's...
i don't have any regrets of doing it in a FTO, it's great to have additional explanations, courses that increase your motivation you every day and to have the feed-back of other exam-sessions. And ok - if you do it at home - it will cost you less we agree, but honestly the cost of the theoretical course is peanuts compared the 'real flying' costs...
Nevermind, props to your decision and good luck!
*admires*