Hi, I'm new here and not very far away from you. (I live in ellington) My Kane has just had all sorts of skin tests etc because his fur was coming out in clumps with bald bits underneath - turned out (over £200 later) he is just having a really bad moult. I've read about the boredom and stress thing, maybe you just have to work through things one at a time - make sure he isn't bored, then think if he is stressed.
I am not very experienced, having only come back to buns after 30+ years but has he just started doing it? is he a single bun? Has anything changed recently in his life/routine?
They are such a worry! I had dogs until recently and have had my horse for 16 years and I'm sure they are nowhere near as much worry.