You can study for as long as you like any of the subjects before sitting any of the exams.
But as soon as you sit one exam you have two years (stand corrected it seems to 18 months) to complete all 14 or you lose them all. You're also only allowed six visits to the exam centre in that time and four attempts at any one of the papers.
I could be wrong it's been a couple of years since I sat mine. But the gist is you have two years (again 18 months) from first sitting of any exam to the last sitting of the final exam.
Last edited by Cool_Hand; 14th Feb 2006 at 23:19.