I contacted a local refurb firm who come to your home and spray the wheels. They won’t remove the tyres nor paint the backs of the rims they aren’t for me. I have had car and motorcycle wheels powdercoated by a Sittingbourne (Kent) firm, McNealy Brown, who are excellent. Apparently you drive the car into them first thing in the morning, they remove the wheels and tyres, blast the wheels and powdercoat them, replace the tyres and wheels and you collect the finished car at 5. I can’t recall the price but the finish is immaculate. They do a ‘chrome effect’ powdercoat which I had done to the rims of a 1951 motorcycle I am restoring. Very very good finish.