If Nottingham are offering accommodation on a first-come first-server basis (which their web site would seem to confirm) that they are in breach of UCAS rules. Specifically, they are in breach of UCAS Business Rule 9 which states:
"Customers must not ask applicants to reply to offers before the normal reply date, regardless of when the offer was made, unless the course starts before 1 September.
Requesting early replies in return for benefits (e.g. priority access to accommodation) is not permitted. Even where courses start before 1 September, providers must allow applicants a reasonable period of time to consider their options and respond."
UCAS have even generated a "best practice" document (
here) to clarify this point which says universities "must not place undue pressure on applicants to reply to offers before 8 June 2023" (that's last year's date), and then lists an example of "placing undue pressure on applicants" of "Operating a ‘first-come-first-served’ accommodation allocation which commences before 8 June 2023."
The stress you're feeling right now is therefore (a) entirely of Nottingham's making and (b) in breach of UCAS rules. I'll write to both the university and UCAS to highlight the breach (as I have done with other universities in the past) but that won't resolve the dilemma you're facing right now.
I guess it all comes down to which is more important to you: the potential of your preferred accommodation, or the potential of a place at Warwick.