Well addressing your questions, PPL training will take you 3/4 months. I took 4 months from start of theory to passing the final skill test (12 Aug to 12 Dec). And I started flying in September so the weather was getting increasingly worse over time. At some point I was grounded for two weeks waiting for the right wx for a long nav solo.
As for the ATPL, I'm currently going through the exams, it will depend a lot on the kind of person that you are and how good you are are retaining facts, also at how much of that thing called "sleep" do you really need. I would say that passing the exams and working at the same time is perfectly possible but I would not bet on the 5 month mark. Allow some more time so you can properly prepare, unfortunately the way the ATPL examinations are structured end up being more like a memory contest, and that requires a lot of hours put into it as simply understanding the concepts and them being able to apply them over a wide range of questions only works for some of the subjects.
As for the points raised by Amarui, I'm pretty sure I know who he is and I'm familiar with what happened there. And he is right about some of the things he pointed out, however I must disagree with some others, the ATO quality has not suffered from the charter business he mentions, he did get unlucky that some of the senior instructors were away on citation flights at the time he wanted to complain, but that was over a small period of time.
Organization I must disagree too, things are well organized, you are however responsible for yourself. Any questions you have will, I'm sure, be diligently answered, but you have to direct them at the right people.
Think your instructor is not up to standard? Schedule a meeting with the head of training.
Need help finding a place to live in town? The girl at the reception will gladly help you (she is partial to Caramel Macchiattos, HEY, I didn't say it was going to be free!)
Got questions about your account with the school, direct them at the head accountant.
Basically, you wont be carried around, but so long as you can point out things and bother to read the student manual to know where to go and who to talk to I'm sure you will find any problems you may have do not get out of hand (This is not a stab at Amarui, his case was slightly different but if he did not want to go into detail I wont either). The instructor he mentions is no longer around however and I (and I'm sure Amarui will agree with me here) can assure you he is not a reflection of the other instructors.