Mine was done at Autobox in Stoke-on-Trent about 9 months ago, my 200k + W203 220 Cdi box was slipping and flarirng, Steve took the box out, stripped it and had a good look first, mine needed a new shaft, TC, the inside of the bell housing refacing, all done within a few weeks as I was not in a rush for the car. At several occasions during the rebuild I called in to have a look at what was going on in there... what an education?
Anyway, it is as good as new now, it's never missed a heartbeat, and, I've towing a 90% matched caravan for quite a few miles with it all over hill and dale....
So, if your car is worth the cost, get it done...
Dave