You would really need to speak to a training school as I'm afraid I know nothing of how the certification works over there. Here you have to be fully qualified in your own specialist area that you intend to teach, which means an advanced ticket. Then it is just the most basic of teaching qualification you need called PTTLLS level 4 which is a weeks course but you will take a month or two after you finish the course to complete all the work. Once that is complete, you do a shadow course, which just means you sit with an instructor while he delivers a part 1 course so you can pick up as many tips as possible and even help you develop your own style as you think of better ways to do the same thing. You will have to sit this shadow for any course you intend to teach, so if you want to teach part 2 scaffolders then you will have to shadow a part 2 course first. The final hurdle is a small first aid ticket, which I hate and always sent someone else to and a CRB check which is just a basic criminal record check to make sure you didn't hang around with Jimmy and Rolph in the 70's and you are good to go.
It may seem fairly long winded and there will be another route available to you through your own American system, but the British training system seems to be in demand abroad at the moment as most seem to want to use it.
What training schools do they have out there and do they ever send instructors abroad to work?