Another aspect local to Syerston/Tollerton is that I believe the motor gliders which operate from Syerston do not have Mode Charlie.
When one is instructing/general handling from Tollerton one usually goes North and East to keep clear of the EMA airspace. This tends to put one in conflict with the motor gliders from Syerston during climb and descent and, I presume, the lack of Mode C may increase controller workload?
Of course any form of control service in the open FIR (what I call "jungle airspace") is an anethma to certain airspace users and indeed whilst instructing VFR I don't particularly want any service (that includes FIS by the way) since extraneous RT chat can be a distraction to the exercise. This does not mean one is not prudent about where one conducts certain exercises or that one never listens out but if there is a thin layer of cloud and you want to operate VMC on top then I am only happy to climb through if I have some sort of radar service.
Sorry to stray a bit off topic but I think this is relevant to the debate.