I converted my SA CPL/IR some years back - had to do all the exams and tests again, but for the Instructors I had to do sufficient ground & flight training at the discretion of an FIC Instuctor (an instrucor who is qualified to train instructors) and a Flight test with a designated CAA examiner, so I didn't have to do the whole 3o flying etc. Did 5 hours flying and about the same ground. Don't think thing will be much different under JAR - best to speak to someone at AOPA UK.