I've agreed with the dealer that before I take delivery of the car I am buying, we will try it with the winter tyres from the car I am trading in - which will have had its summer tyres put back on by then.
Would I be right in thinking that, given that my speed will be overstated when running with the winter tyres from the old car on the new one, so too will the odometer reading? It will be more difficult to live with that, I think, than with a slightly exaggerated speed display. Or is mileage measured in some other way?
Thanks to you both for your help.
A pity I did not catch the 1.4SE while it still had 15 inch wheels. 175/65R14s like mine were the recommended winter tyres if you had 185/55R15 wide-profile summer wheels, with the resulting wheel plus tyre diameter more or less identical on the two combinations of contrasting wheel and tyre sizes. Not all change is for the better, I think.