I've had a series of nightmares with my old landlord. We moved out 5th March and played everything by the book - gave two months' notice from the first of March, paid the rent for March, etc etc.. She's let it slip that she's visited the flat since we moved out without our permission. She's also gone mental because we've given "her" keys to the letting agent to show people round. If she's broken the contract by doing this (I think she has) then can I say "you've broken the contract, keep the deposit and get lost"? I just want to move on and forget about it, but is it within my rights to do that?