Mr Sims, if your an ITF member, probably best to attend an ITF Umpires Course. the last one in the UK last year Feb was very informative, it was a very detailed education. even though i have had tournament experience as a competitor and an assistant/umpire, there was a lot to take in and take on.
the BTC as such have never held an Umpires Course that i know of as the BTC is the Council for Taekwon-Do/Taekwondo/Tae Kwon Do in the UK. it consists of difference styles of TKD (ITF, WTF & independant). the only part the BTC plays is Instructor courses so UK instructors are legally registered and checked with the ability to instruct properly. they don't get involved with the actual teachings, just the legal stuff, CRB checks, health and safety, first aid qualification... etc.
the ITF directly host Umpire Courses for the ITF, there is no rule to where you take it, recently other members and masters were given certification and permission to host Umpire Courses so there might be another nearer to you but as it stands, the one that Mr Riordan mentioned is probably the nearest one.
In Australia, our INO president, Master Muleta, has set up, in the last few years, a very good umpiring course system. Every official competition (States & Nationals) is ran over 2 days. Master Muleta runs an umpiring course on the Saturday (all theory) then the practical is conducted during the sunday's competition. I can attest that the umpiring standard has certainly risen, and a few of us don't have anymore to umpire all bouts. Funny that the only ones complaining now about poor umpiring are those that never bother to attend the courses....
We also hosted Master Gallaraga in June 2006. I recommand his course; very informative but still fun to attend.
Its a shame you missed the last one in Feb 07 as Master Harry was present for the course. there might be another UK hosted one as there are members within the UK that can host ITF Umpire Courses.
Check with the ITUK to see if they know of any UK based seminars in regards to distance but then saying that, sometimes it can be worth the travel as you can learn new and/or different things from other National groups. Taekwon