Thank you all for your help.
Since making this post a number of things have happened. The nerve in my left thigh has been 'firing' (my Dr's words) almost constantly most days. It causes so much discomfort that I can't sit or stand for more than about 15 minutes. I have found that walking actually helps.
I spoke to my Dad, who is a TPI (Totally Permanently Incapacitated) Veteran. He too has similar issues in the same places in his back, only 20 years more advanced. As a Veteran, he is entitled to various assistance through the Department of Veteran Affairs, one of which is a rehabilitation gym. He spoke to the owner and got me in on his DVA card, a deal done to ensure and encourage Veterans to participate.
I have had an assessment there which shows significant differences in my strength and reach on my left arm, but on the whole I am healthy. I have been going for 3 weeks now and have a special program that helps strengthen the muscles in my arms, back and tummy to help support my spine.
For the first two weeks I noticed very little difference, but after last week I was headache free (I had had a headache for 11 days prior to this) and am able to sit for longer periods. I walk as much as I can and am doing a supervised pilates program, again working on the core muscles.
I can't say that it has fixed things, but I am hoping it will delay any possible operation that may be in the future.
Thank you all for your help and advice.