I had a long chat with my instructor about this. Well I say chat, I didn't ask and was a bit miffed that we were stood around instead of riding. Anyways, he said there was a couple of ways. First is to go on a residential course and get certified. He did say it was bloody expensive. And then find a school that is willing for you to work through. Second was paying a school to let you tag along, learn and would certify that you had enough knowledge to be put through the test. Or you may be lucky and find a school that would let you work for free. The first option sounded the best to me but he seemed to think the instructors who have only done the course and not learnt with real students where the worst kind. He mentioned that £100 a day before deductions was the going rate. This is second hand info so do check it out before you make any decisions.