Hi,
I did mine in 5 months, full time at home though. The 1st module is the hardest and once you've done that one and learnt what's involved the second is much easier.
I reckon I managed 3-4 hours a day 5-6 days a week. I think the hardest thing for me was not knowing what to expect, how much I needed to revise and partially being scared of the actually exams.
I can tell you though, the BGS 2 week revision week is amazing, it's concise, in depth and worth every second there. You will work, life, eat and breath the ATPL subjects and by the time you get to the 1st exam on the Monday morning you will be in the best position you can to pass the exams.
Once you've done Module 1, Module 2 is alot easier, you can study smart and know what works for you.
The Question bank is invaluable as I reckon a good proportion of all the exams questions are word for word on there, however, learning the questions and answers may make you pass the exams but wont be much use in the real world, knowing the fundementals are essential.
All I can say is find what works best for you, study the way that suits you and set yourself a realistic time scale for revising and then sitting the exams. I know it's all very well sitting on the other side of the fence having passed the exams, but I loved every moment of the study, the revision and the ground school.
If you love flying then you will have no troubles in finding the motivation to study.
Good luck and remember the end goal...