Many thanks for that suggestion, it sounds very sensible.
I believe also that there should be a 'gaiter' fitted to the top of the heater intake, presumably to try to ensure outside air gets into the heater element rather than engine romm hot air. Mine is missing and theer are only remnants of it left. I will flush the radiator with Wynn's, insulate the gearbox tunnel and try to fit a new gaiter (if I can find one).
