Shugs: I had exactly the same experience as Andy. Although I had no random injuries which had cause for concern, I've also been sent to the CAA immediately (they seem to want to get everyone to do this asap) - my CAA medical is on Friday. A trip to Gatwick for you soon I think...
Abz217 - Most likely is that you'll be asked to book a Stage 1 date very shortly after applying (once you are 18). It takes a few months to get through all the selection and medicals (I started this stuff in October 2008 and only am just finishing off stuff now), and then you'll have to wait for a course date, so I imagine by that point, you'll be 21 by the time the radar licence stuff comes along. And if you don't make it first time, it'll take even longer...
Hope that helps!