If by that you mean Trimix, John, then go to the BSAC website and search for "trimix" -links such as
this one clearly state that qualifications from other organisations are recognised by the BSAC and can be used on BSAC dives..
When it comes to rebreathers, they only sanction CE-approved ones - the Inspiration and a couple of SCRs.. there's been discussions on the board of how daft this is, since a single modification to a rebreather voids the CE marking, and just about everybody tinkers with their gear..
Incidentally, I can't see the problem with CB's situation - most of Dive Leader is about rescue skills and leading inexperienced divers. What on Earth has that got to do with Trimix and rebreathers??