Hi Whirls
As long as youve registerd with a ground school and started studying for the IR (Distance learing is ok) you can complete the course under ammendment 3 JAR FCL 2. There are time limits of course, you need to complete all the theory exams with in 18 months after passing the first exam and then gain the IR within 36 months after completing all the IR exams.
I would strongly advise getting it in writting from the CAA though. Plus if you done the CPL JAR exams you may get some credits as one of the other posters here did.