With my student halls and everyone else in Liverpool, (to my knowledge) it was that your contract started on the 19th of September (start of freshers week for me) until 8th of July. Between those dates I could stay in the flat all day everyday if I wanted to. Besides my course didn't have reading weeks (half terms) and as such I only went home for Christmas and Easter.
My house contract for next year started 22nd of July, so I can now go and collect my keys, move in anytime I want between now and the start of my course. But we've decided to move in on the 10th of September, two weeks before we start Uni again. The other poster described how houses work so I wont.