Hi Serendipity,
I'm usually a lurker rather than a poster but I've got to ask you where you are in the Vale.Where do you stable.
I'm from Dinas Powis but now living in Canada but any post from South Wales just gets me posting. I'm afraid i can't help with advice about the trimming . 17 years ago when I left i'd suggest the Steve Llangford as a great blacksmith , but i don't know any trimmers.