Lodger Agreement

Tenancy Deposits

Hi All, 

My daughter recently ended her agreement. She was given a licence to occupy as the LL reserved the right to occupy a room in the house when he visited from abroad, it was very much a "home made" arrangement however the landlord is a barrister. The licence stipulated three months notice were required however my daughter asked to give one month and this was agreed. The landlord has now come back after she's left and said he may retain her deposit if he doesn't find a replacement quickly - this wasn't mentioned when he accepted the one month notice. 

Apart from the fact that I consider his behaviour to be immoral, can he now enforce the terms of the licence agreement after agreeing to the one month. I've only ever used AST's so have no knowledge of lodger agreements or any legislation governing them. 

Thanks