I think you've made the right decision, especially if you're planning on keeping the car for more than a year or two.
My experience was that once the 'box started to show signs of going, it deteriorated pretty quickly. I had a gearbox oil flush, and that just accelerated the problem, so I'd suggest not doing too many miles in it before you put it in to get it fixed.
I'd recommend Mackies, who did mine, and here's the link to their website
http://www.mackie-transmission.com
Although this cost 3k, and is in Glasgow, it's much more than a refurb - the 'box is completely dismantled and rebuilt, with any suspect parts replaced and in some cases upgraded (e.g. the torque converter). I've been running it for six months now, and am completely happy with the job they did. If you need any more info on them, there's a bit more on the thread I started when mine started to go - or just contact me directly.
Brian9, the Laird, Davids'8, and probably PsYcHe also know quite a bit about these guys, so they may be along with more info - I think they were trying to negotiate a group discount at one point
