I didn't have that problem - I had sciatica, but there was a regular physio and football FA physio on my course specifically to learn it. I think they some studies on their official sites (there are a couple of registers of practitioners) I did my training 15 years ago for home use only. I think it was reported to be twice as fast as surgery. It's a combo of Bowen and specific stretching exerises from what I remember. Pretty cheap and we'll worth finding an experience practitioner.
I'm on my phone and can't look but I think there are also some YouTube vids as it is quite a well known method now.
Good luck!
Thanks Milena - for anyone else in the UK I managed to order from amritanutrition.co.uk - I had to e-mail them get manually affiliated to a practitioner before I could order but this was quickly done.