I'm the one with the Proflex and the Clockwork.
Find a local powder coater and give them a ring. First question should be, have they done bike frames before, if yes they'll know what's involved (hopefully). Then ask if they will strip the frame and re coat, or if they'll need you to strip it.
Basically, if it needs stripping before it goes, use a chemical stripper to get all the old paint off, and give it a rub down Worth medium wire wool and soapy water. That will wash off all the paint stripper and smooth the surface in one go.
Then mask all the threads for bottle cages etc., BB and head tube. (don't forget the rear mech hanger threads)
Smaller threads can be masked with a tight roll of thin card. Larger ones can be done the same, but put a roll of card in the hole and then pack it with newspaper or similar.
Cost for stripping and re coating should be around £30-£40.
Hope that helps.
WANTED: RS Mag 21 with 1/18" unthreaded steerer | USE Stealth forks or spare parts