I have been trying to find this out, but no joy so far.
DS has deferred offers for Sept 2021 (is taking a gap year).
If he accepts two as his first and insurance choices now, then gets the grades in July/August, is he then contractually bound to a university, or is there a later stage, where everything is finally signed/ agreed etc?
He's now wavering about his subject choice and thinking of reapplying for something different in the 2020-21 UCAS cycle, but would like to wait to see what his grades are first.