Thank you thank you DJ and Mark
It worked, well sort of, I have the version 2.5 installer and I used that to reinstall (This was left on my computer as I had loads of trouble updating to version 3 previously) and that worked and i redownloaded some books ok. I then tried updating to V3 and that basically just went back to how it was last night. So I went through the process again and am happy to leave it on version 2.5 as I only really use it for Library books as I mainly use Calibre.
