Six Weeks
CATS brush-ups are 3x1 week this is the week before the exams so you will only need to take the days off for exams you are sitting, so it's not quite 6 weeks, Bristol I believe has 2x2 week brush-ups with exams the following week but with multiple exams on all days not sure about the others. As you pointed out the 10% is mandatory and Instructors must be part of the school and teaching should be carried out at the approved location. You will find a lot of people in the same position as yourself trying to balance the need to earn money with the need to get on with training unfortunately something nearly always has to give.