Thanks for all the input guys, I appreciate it.
I haven't heard from her today at all, which I thought may have been a good sign, however a friend of mine phoned me to let me know that she had approached him this morning asking if he was able to edit out my watermark from the proofs that I had sent over to her so that she could get them printed. My assumption is that she didn't know that we are friends and that it would get back to me, because she told him that I had sent her the proofs before Christmas (I didn't) and that she has not been able to get hold of me since in order to let me know what she wants printed, and so she is left with a selection of unusable proofs that she wants printing. He told her he wasn't able to and then contacted me. He wasn't aware that there had been an issue and assumed she was just trying to pull a fast one, which is now what I'm starting to think to, however I'm still sort of over a barrel because I can't prove that she has done this and if she still demands a refund or a reshoot I guess I'm sort of obligated, meaning I will either lose out on the money or end up working a load more hours for free. I'm not so bothered about the money, tbh. To get this over with I'd happily give it back, but I feel reluctant knowing that someone is obviously trying to do me over on this one, and doesn't have a genuine complaint.