Pete., I know exactly what you are experiencing with Arthritis in your lower back, I've suffered like that on and off for many years, I'm currently going through a good period. I find that when I'm in the shed keeping busy, I tend to forget all my many aches and pains, unfortunately at the moment the torn rotator cuff in my right shoulder is no longer responding to Cortisone injections so I'm due for surgery on February the 4th. in the meantime I'm taking things easy. Hopefully now you will no longer be sat at a desk things will improve dramatically.
Nothing but heaven itself is better than a friend who is really a friend. - Plautus