The exams results are received just AFTER the deadline for applying for the next month's exam sitting. Therefore, you have to wait two months before you can resit!
Personally, I think two modules for 14 subjects to daft; why not split it down into three or even four sittings, still leaving two sittings for retakes. The CAA don't care which order and when you do the exams. I did them to minimise days off and days away i.e. I sat the subjects on one day at a time!
If you have more than three atempts per subject and more than six sittings, I believe you have to start the whole course again and retake all the exams you'd originally passed.
Cheers
Whirls