This makes no sense at present.
In what capacity have you been asked to fly them? Why do you need a medical if you hold a CAA class 2?
If you are simply flying them as a PPL then there are restrictions - max 25nm from base, no landaways, min hours (can't remember what they are now), &c &c. They'll be in an ACP somewhere - ACP22 for CCF but I can't remember for ATC. There's no requirement for an RAF medical.
If you've been recruited as an AEF pilot or VGS instructor - which I doubt, as neither system seems desperate for aircrew at the moment - then they will tell you what's required.
Tim