They probably won't give you much/anything to do before the course starts. I study business at Warwick, so a bit different, but in the weeks leading up to my course starting we had some 'pre-arrival tasks' to do, which more or less were just registering for services on campus, like the health centre, or uploading a photo so you can get an ID card printed. We did have a math booster module to complete which reiterated what was taught at A-Level Math, but obviously a business degree is more numbers-oriented than law so I doubt you would have this. I would expect there won't be any work expected of you before the course begins. Anyways, law students get a reading week every so often where there are no classes just to catch up on readings, because you can expect a lot of reading each week