Backache early in the morning

I am waking up in the early hours with lower back pain. I tried a memory foam mattress and my wife found it too hot so we bought a pocket sprung one which is quite firm. On the label it says luxury comfort wool, with white polyester, over 1200 pocket springs, polyester blended with lambs wool and Silver technology, handmade. It also has a built in mattress topper.
My wife says it is far too hard for her, we were told it was a medium firmness but it is very firm.
What would you recommend please neither of us can get a good nights sleep. Our budget is roughly £800
Richard