Are you saying the lease contained a break clause allowing either party to give two months notice to end the lease? If so this should still be able to be enforced after the end of the fixed term, so your notice should still stand. I'm not sure how this stands with contracting out though - ie if you haven't contracted out correctly whether a break clause contrary to s25 LTA 1954 can still be enforced without a s25 notice. Hopefully someone can advise.
I think MrJohnnyB is exploring whether you have a granted a licence or a lease for the premises. You mentioned having to tidy up - does this mean you have always had free access to the rooms without needing the tenants consent?
If it sounds like I know what I am talking about........I don't.