I did in in Mexico. Great clinic, they do it for 30+ people a month. Smooth and top notch doctors. You'll have to google as I can't put links on here, just google 'MS HSCT Mexico'. Russia is also good, the doctor there, Fedorenko, is a bit of a legend and he's done lots of articles and interviews about it.
HSCT is basically they give you 4 treatments of low dose chemotherapy, just enough to kill your immune system. MS is an auto-immune problem, so it kills the faulty system. They take your own stem cells, so theres no chance of rejection, and after the chemo they put them back in to kickstart your new MS free immune system.
Unfortunately it's not a first line treatment yet in the UK. It probably will be in the next few years but for now it isn't.
The aim is to stop/halt the MS. If any old damage gets better (it did in my case) then that's a bonus, but the aim is to stop it. So the earlier the better.
Most people fundraise. Lots of people in the UK do, have a google. There's a few of us on here that have done it/are doing it.