Hello Hugo,
I am so sorry to hear you are still suffering physically and from the loss of your data.
Have you tried a steroid injection in your knee? I don't know the cause of the pain you have there but assume it is arthritis. I have this problem and steroid injections can make a great difference. They ease the stiffness and the pain clears up. They last about 4-5 months from my experience.
The NHS is worse up here than in North Wales. They cannot recruit doctors, or consultants in the local hospital. They built a brand new state of the art hospital which hasn't been open long. It is run by agency staff and locums. My GP practice is down to one partner now. Four years ago there were four partners, the senior one left to work in Holywell, Flintshire, just after I moved here.
I seem to recall there are some good computer repair places in Chester. This one has my recommendation:
https://www.computerbuddies.co.uk/If all else fails it might be worth a call to them.
A friend of mine had the same problem with an old hard drive of his. It died and he lost everything as well. I still hear about the things he misses, old television programmes especially.
I hope body and computer are both better soon.
Helig.