yes the hotel i was staying in cost $300 per night, not £.
The initial contact from AA was a voicemail left on my phone saying- Friday flight cancelled, we've rebooked you on the saturday daytime flight via heathrow. when I phoned to check and get an email confirmation of exactly what flights i was on, I asked about the hotel situation etc... and all i was told is you need to file for compensation when you get home and was no offer of help or them putting me up in a hotel.
I wasnt checking out my hotel and hanging round the airport over night when it wasnt my fault. guess i'll just need to wait and see what happens.