I took mine out last year and had a local fire protection company refill it. The company dealt with fume hood fire systems for labs and such. They didn't have the original halon in stock (1205???), but refilled it with 1211. They charged almost $200 for the refill. Come to find out that my valve leaked, and the bottle drained in a weeks time. I'm going to replace it with a new system in the near term.
I tried to get the original company (someone in the UK) to refil it, and struck out. They no longer refill bottles as old as mine. I contacted Fire Bottle and they said the same thing. They can't fill a bottle this old either. Damn. Looks like it time to go buy the new one. Gonna check out CV Products right now.