I have a Canon LiDE 50 and there is no 64-bit driver for it. However there is for the LiDE 60, and it works perfectly - you just have to use the 'have disk' driver install method and ignore the warnings.
Thanks for the suggestion, I've tried several Lide drivers and no good I'm afraid, I've also been on the US Canon site and that didn't help either. Real shame as the Lide 20 is a really good low cost scanner. I've emailed Canon twice to see if there is a solution but they can't be bothered to reply. Up to this point I was always a Canon supporter owning a Canon camera, printer & Scanner. Looks like I'm going to have to look elsewhere.
You could try Vuescan.
It has support for the Lide 20.
The generic Windows driver might work for you.