Andrew . . .
I have just checked the precise dimensions of my Anglia body shell, also the wheelbase and the wheel diameter. The Tamiya Lotus Super 7 wheels have a diameter of 14.5 mm, which is exactly 0.75 mm too large, because the 1:24 scale measurement should be 13.75 mm
By taking 14.5 mm and multiplying by 24, this gives 348 mm . . . which is 13.70 inches for the full size road wheel.
So to summarise: 13 inch wheel = 330 mm and divide by 24 = 13.75 mm
For me personally, I can live with the 0.75 mm being slightly too large for the Tamiya wheels on my Anglia build . . .
I managed to pick up a Lotus Super 7 donor kit for £15 and I noticed the set of wheels and tyres from Motobitz are also £15 . . .
David