Thank you both so much for your help!

Thanks, they have replied with: under Section 8 of the housing act 2004 we can seek eviction under grounds 10 of the Schedule 2 to the Housing Act 1988.... is this correct?!

Thanks for you replies! Unfortunately i have some new questions! My girlfriend received a letter from her letting agency last night. They pointed to clause 8 in her contract and said she is in breach of this. this claus especifies that she shall not sublet, etc, and that she will not be living there. They have said that there was a man living there (Me) and that this is in breach. Obviously i have stayed round there alot, but i am certainly not living there! Do you know how they can prove this? and is it unlawful or wrong for them to threaten serving notice based on clause 8 if she does not pay by wednesday?!

... well my girlfriend's landord has said he will issue my girlfriend with notice, 2 months into a 12 month agreement on the basis that the second month's rent is currently 1 week late, and will not be paid for another week. Is he able to do this? I know a landlord is not supposed to be able to do this in the first 6 months, but does a late payment provide grounds for him to do this?