You could try the people that actually do the coating, they're really helpful.
Spoke with them some time ago when they came round my firm flogging their services, asked the rep. about fork coatings, no prob. so long as you strip the forks down to the stanchions yourself - (they've done lots.)
The firm is Tecvac -
www.tecvac.co.uk tel:01954 233700 based in Cambs.
Hope this is of some use.
Pete