Faye, I compete my mare in a Pelham- not only is it legal, but REQUIRED after fourth level!
I have ridden the horse in question, and the Boucher is nice, but still isn't quite perfect for her! I believe Ak hasn't tried a Pelham yet? I think she is planning to. (Ak, I'd let you borrow mine but it's about two-and-a-quarter inches too small for your gorgeous giant!) i'm not a fan of the loose-ring, especially for jumping- I find the horse can get quite wiggly from the lack of support when doing some exercises, and my horse certainly doesn't like it! I would suggest a fixed ring or Pelham. Perhaps a full-cheek for jumping ( I use different bits on my mare for the different phases of eventing- she likes it that way! )