Thanks for all the comments.
The thing is it's always kept in the garage, and I've only really left it "dirty" once. I say Dirty, I mean taking it out about 3 weekends on the trot in the DRY without washing and polishing it.
I used autoglym resin posih on the wheels after I'd cleaned them in the past, as I've done this on cars and bikes over the years and it has alwasy seemed to offer a good level of pretection which is whats confused me.
I'll have a go with autosol at the weekend, well next week as I'm out of work as of today! And see what I can do with them.
If not, then its down to get them poswer coated.
I'll try and get some pics and update you.
Cheers,
JC