Thanks everyone for the very useful information and the humorous responses. All incredibly useful.
We caught the end of the European heatwave in June this year. 40 deg with roof down and heater on to pull hot air from the engine plus all the heat coming through gaps around the tunnel was a bit much so thought i might be able to at least solve one problem. Can't expect the engine not to want to overheat in those conditions really or can I?
Had a wheel fall off the GT6 last weekend returning from a run, so back into the garage it goes.
Had a shoe fall off the daughter's horse too, but at least the GT6 didn't try to bite or kick me as I worked on it...