Ok it doesn't specifically say no however, the rule book says uniform or hunting dress with white, fawn or cream breeches. Given that hunting dress is tweed or black/blue jacket. However, hunts like (for example Berkeley have gold lapels for the huntsmen and browbands for the horses) do but they have to be earned.....
So I would say no based on tradition, depends on how up-tight the judge and the venue holder are. Personally I am too traditional to try and be different!
BE say no you cant wear them they are reserved for GB event team members... we had to find out when getting clothing for a different british team and we wanted to make sure we could wear it when we got home so rang and asked... not sure about BD.. i think one of our other team members rang them to ask and they also said no but dont quote me...