They've really exploded in British collection in recent years. Hamerton has over a dozen in one (not especially large) aviary. I first saw them at Blackbrook and got very excited - now they seem to be everywhere. But they are, as you say, absolute gems - a really charismatic species.
they are magnificent birds. Is their becoming common in the UK a case of one or two pairs being really productive and the offspring being supplied other collections, or are they just being imported a lot? If the former, I can foresee them quietly disappearing again after the productive pairs die off