I don't think you'll even need to go through the CAA with this one. I've just glanced at the OPs public profile and he flies Vigilent T1 motor-gliders, so its a fair assumption that he's either a Civilian Gliding Instructor or an RAFVR(T) officer at a Volunteer Gliding School for the Air Cadets.
If so, its easily possible to pass the buck, and speak to either the Chief Flying Instructor or the Commanding Officer, and let them investigate and take action. After all, its the CO's head on the block, and not the OPs. VGS units are administered by the MAA as opposed to the CAA, so certain civilian licences and ratings might not actually be required, which means that the implications might not be as alarming as they would perhaps appear.