You need to apply to IAA for permission to do the course, the form is RPPLF399E which unhelpfully is not on the IAA website. On track provided the form for me. They also managed the process with the IAA. Once you do the course (3 days), you still have to do an assessment of competence flight with a senior examiner (basically a mock LST / PC). Like most things in aviation, it's overly complicated but once you know the process it's manageable.