If they are cast I don't know if you will get them done.
A1 anodising near me are good. They always used to say no if you asked them
to anodise cast ali. I had them do some calipers, which are cast, they didn't
charge me as they weren't happy with the dye; they look pretty good but the
dye colour was a bit hazy, best bit[if your a cheap skate like me] they didn't
charge because of it.
A1 Anodising I can't remember the name of the road, but it's in Crawley.
I have someones frame and forks here, with a gsxr front end A1 re-anodised
and gold dyed, they were pretty scratched, the old zig zag scratches, they
now look great.