Roy I have just dug out my Clarkson book, are you referring disk wheel and cup wheel part numbers 92612 and 92613, if you are they are just Clarkson reference numbers and will mean nothing to anyone outside the factory.. in the back of the book, page 27 in my copy are the British standard wheel symbols, these are what you need to use when specifying a wheel. Luckily on page 26 they list the full spec for wheels they used, cup wheel 38A150L8VBE, if they were good enough for Clarkson they will do the job.