scrap that i've found the reason for the dodgy reading, the ECT sensor in the head had nothing plugged into it and when i found the plug i found another ECT sensor hanging on the end of it :doh:
i suspect it was someones attampt at a hot start fix but it wasnt doing my mpg any favours and since plugging in correctly seems to still start fine hot or cold. it had a repalcement engine last year so heres hoping that the old engine had hot start trouble and not this one
