Hello, I am a solicitor with 20 years experience. I will try to answer your question
OK are yo happy for her to leave early? I expect that you are in the circumstances. I think that although if she is a tenant you are required to protect her deposit, and she could seek compensation for your not doing so, it is unlikely that her claim would be successful. These sorts of claims are much leas successful now that they have been in the past. If you just return her deposit to her when she leaves it is unlikely that she will be able to successfully obtain further money from you.