Simon, I am pretty sure I have a 10" mini wheel with a new tyre on it. I also have a set of four alloy minilte type mini wheels that I was going to use to build a trailer but found that they are not really suitable because they are quite wide, 5 or 5.5J I think and Indespension doesn't work with them. You would need a long axle and I wouldn't want to trust it. The good news is, I also live in Credton but I am away until the 8th March. If you are still in need then PM me and we can arrange to meet up.
