That looks quality chunkeboi!
As said powder coating is the way forward if you can justify spending that bit extra,will last a lot longer and you won't have to worry bout stonechips etc.
I think £50 seems wayyyy too much,especially seeing as your rims ain't even that badly damaged,most bodyshops charge roughly £25 per wheel so £50 seems extortionate!I'd definatly look at other bodyshops/alloy specialists before forking out the money,and worst comes to the worst,get a mate or someone off here to do it for ya on the cheap

.I've refurbed 4 sets of rims now just using halfrauds spray cans and had fairly decent results as I'm too skint to fork out for a proper refurb.