DS has 4 offers - Durham, UCL, Warwick, Nottingham. He has told me that he doesn't need/want to decide between them until early June. This is partly because he is struggling with the decision (he will be talking to someone at school about this), but also because he has applied for a sports scholarship at one of them, and won't know if he's got it until the end of May. (The others don't open their sport scholarship processes until later in the year).
In the meantime, Nottingham is opening its accommodation bookings process from early April. I haven't yet checked when the others open their bookings - there is so much marketing material on university websites its sometimes difficult to look things up quickly and get a straight answer. But in general, if he waits until to the last minute to decide on his firm and insurance choices, will he miss out on the best accommodation?