Roger, thank you for a very informative technical piece on the Duratec cooling system, very much appreciated.
And thanks to everyone for your comments which I have found to be most interesting.
Armed with this knowledge I will now do some "tweaking" until I find the sweet spot.
(And, I know realise just how the tiniest amount of bodywork alteration on an F1 car can have a dramatic effect!).
Thanks again
Geof