This is why I have a Line6 Toneport at home, no external amp to make noise but you can crank it as loud as your ears can take it.
And as for that law stuff... sorry but that's tripe. It's not a part of our culture as it is in America, we might complain to the hilt about things like that but nobody here would instinctively reach for the Lawyerphone and sue someone.
If it says in the contract that you can't have an amp... then I reiterate what I said: speak to reception and ask if it's ok as long as you keep it to reasonablr hi-fi/tv volumes within reasonable hours, say pre 11-pm? If you go to them and be responsible and human about it, they're far more likely to accomodate you.
This rule of NO AMPS EVER in halls like that is bollocks, you can make just as much noise (or more) with a cranked stereo than a lot of guitar players will make with their amps from my experience.