It seems as if my suspicions might be right about the same bolt pattern on the wheels of 6pdr guns and F8 CMPs. Have a look at
this truck, which ought to be on 9.00-13 tyres. If the description of this 11 cab F8 is correct in mentioning 10 inch wheels, it would seem he has fitted four NOS 8.25-10 tyres and rims from a 6pdr gun! Where did he find them?!?
This would be an interesting buy for the money.