I wanted to advise the OP that she can ring the police's non-emergency number & ask for advice. I've done that when it was hard to know what the police might/not be interested in, what they could do, when it would be OK to report something via that line or 999 - that sort of thing. Even if they wouldn't want to get involved, they can advise you what's acceptable for you to say or do if, for example, you were with the horse & A appeared, or if she continues to harass you with messages & demands.
I hope the OP comes back. That was a lovely thread. And to the people moaning about this thread: I don't think it's us who need to find something else to do. You're not interested in a thread? Then move on & find one you do like.