Hey,
I'm sure you'll be joining us in September, think positive!
My exams didn't finish until 13th June. Some people finish earlier and some later. I think the latest they go is about the 19th June. Lectures and that tend to finish a bit earlier, I had no lectures for about two weeks before my exams. It depends what subject your doing as well, some subjects finish more than others.
Not sure whether uni would be sympathetic. Depends what the opportunity is, how you go about asking, and how you've acted during the year i guess. If you've been good student and nice when dealing with the staff responsible for giving you leeway your chances are greater! My instinct would be they wont grant leeway. However, i may (and probably am!) completely wrong.
Sorry i've not been much help!