Mate, go to as many open days as you can. I remember all of my open days made the uni's look awesome. But then the last one i went to was way beyond the others (which i hadn't thought possible at the time), so i went there.
Aye London is awesome for the student lifestyle, and i wouldn't worry about the costs - sure its alot, but you can pay it back as/when you earn the money (or in your case have rents pay for it - even better). My degree won't get me a high paying job, but i loved every minute of it, and it'll help me get into a more interesting career.
To be honest mate, your dad and siblings should be the ones your asking, if they have studied the same subject (or similar) they should have a good idea or the more respected universities. Anyone that studys to that level usually knows how their university stands amongst others etc. (Or alternatively league tables on websites such as The Times are quite comprehensive with details on necessary grades, teaching standards, student satisfaction etc).
/Gand
I'm no hater Tai, for once im impressed hah.