Hi try Doug & Simon Vieweg. Excellent at handling the horses and very qualified! their practice is called Westrow Equine, have used them for years and so have most of my friends
Chris Keates and Nat Heal are both IMO very good Nat is especially gentle and kind and Chris has done a v good job on my welsh sec A's hideous mouth (not my fault i brought him like that!) PM me if you want any opinions on other dentists - there are a few that i would certainly steer you clear of !