Many thanks for all the comments, suggestions and support I've received, it really is much appreciated.
With regards to physio/exercise, I've undergone numerous bouts of physio over the past several years, none of them successful. In fact my last physio admitted she was baffled by some of the symptoms I was showing; this was before my MRI scan. I'm currently awaiting a further course in January.
In terms of surgery, following my MRI, the surgeon I was under, who initially seemed pretty convinced I was some sort of moaner, declared that I did have problems but he couldn't help me; I'd previously had the same from another orthopaedic surgeon. No luck there then.
I've undergone various bouts of acupuncture, sometimes with slight results, sometimes with none. I've been having chiropractic for years now, but it aggravates my condition nearly as often as it helps.
I used to weight train regularly, but after my problems started found that pretty much everything I did aggravated something; I get muscle spasms through both arms, legs, pelvis (including locking of pelvis and associated - and rather unpleasant - problems). I get really bad neck and back pain & spasms, tingling in my face, arms & legs, problems with my hands & feet....you get the picture. Anyway, going private would be the only option for me in the UK and to do that I'd have to sell the Alembic anyway! Also, I used to do a job where I was involved in assessing people who had all sorts of physical disabilites, and in every single instance where someone had had a back op (I'm talking hundreds), even where it had initially caused an improvement, it had eventually deteriorated way past the original point, so I'm rather antsy about back surgery. I'm glad to hear it worked out for you though Southpaw, and more power to you; hopefully with the work you're doing it'll keep improving. It may be that top notch surgeons have something to do with this, as the ones I've met have showed no interest given that I'm still able to walk. Still, hopefully they are helping those who are worse than me, so I mustn't grumble.
Of the other remedies suggested, I will try and get hold of a slider strap. If that doesn't work, then I may just have to sell her; as much as I love the bass it's not worth the pain! Almost, but not quite...it will be a sad, sad day if it comes to that however. Fingers crossed.
Once again, thanks to all for your comments, they're really much appreciated.