bloody hell paul fair play to u mate most people would just give up. Can u not get a phizio on the nhs?surely they could help u with best exercises etc.

So we know u wont be training to get big and v have a massive major injury... My advice would not be to start in the gym but maybe try a beginners circuit training or something like yoga or pilaties(spelling lol) i know its really girly but i think u need to build up strength before u lift weights. I would concentrate on your core strength as that will help relieve pressure on your back when u start with the weights.

I know u got your heart set on the gym but find out about the classes i mentioned above and only do really really really basic light weights. If u wanna tone up do more reps with a light weight. Hope thats helps but remember its a long term game esp with your injury. Concentrate on doing things properly and try and speak to a physio.