Hi guys, many thanks for your replies, it's much appreciated. I am still a bit confused as the best way to solve this. I would prefer to use Calibre completely without using Mobipocket software so copying to and from the Cybook is a good idea but a little impractical (although I will try it to confirm your theory pdurrant - cheers).
How do I disable the mobipocket plugin ( i know it's a thick question but I can't seem to find where to do it)
Thanks again for all your advice guys