I'm pretty sure you won't be chilling at college. If you're doing ICAS, my colleagues that have been down this route inform me that it's an intense two months. Studying nearly every evening for 2 months sounds hellish. The college usually reports back to your firm on mock results (progress tests), so you can't really slack off.
Having said that, I much prefer study leave over working on an audit where everything is going wrong, and the client's being a dick.