Fussell's stopped producing this product a number of years ago, but these heels were found at the back of the shop in the original box, untouched.
Measurements as follows (in order smallest to largest):
Size 4: 5.3cm across x 5.8cm long;
Size 6: 5.8cm across x 6cm long;
Size 8: 6.2cm across x 6.2cm long;
Size 10: 6.3cm across x 6.5cm long;
Size 2 3/4: 7.2cm across x 7.5cm long;
Size 2 7/8: 7.5cm across x 7.6cm long.