[eeedelli]

Oh! I didn't realise it was adjustable. Thanks for that info.

Mind you, if I adjust it one way (e.g. to make it open more, so as to get more heat (assuming there is some more movement available on the valve)) then that would suggest that the inability to cut off all flow in summer would be even worse than it is now, wouldn't it ... or does it somehow increase the range of movement at both ends of travel?

Are there different holes along the lever arm so as to multiply the movement like a gearing ratio? If so, perhaps changing to a hole nearer to the pivot would be all I need to do, as the same amount of movement of the bowden wire would then move the valve's arm over a greater angle.

I don't expect to get to this in a hurry, though, as I've just done my back in (again - regular problem) so crawling around under the dash certainly isn't going to happen any day soon, until it settles down again.