Cron, sorry, I started to answer this yesterday, but I was too busy, and I thought someone else would probably reply anyway. Nothing to do with Birmingham, honest!
OK, all the following is courtesy of Tiger Helicopters at Shobden, but it should be right.
You now need a CPL(H) before you can go for an instructors rating. For that you need 155 hours total time including 50 hours P1, then a pass in the CPL ground exams. If you get a partial pass before sometime in 2001 you can do the old CAA exams; after that it'll be JAR. You then do a 30 hour Commercial Modular Course and then the Commercial Skill Test. If you then want to instruct you have to have a total of 300 hours, 200 P1; then you can do a Flying Instructor course - 25 hours dual instruction, approx 50 hours ground instruction. And you need a Class 1 medical for any instructing or commercial work, so best to make sure you can get that first.
I'll try to answer anything else I can but I'm not an expert; just a fellow helo instructor wannabe.