Thank's for your suggestions warren. I have all power saving options I can find in Windows turned off. There is an option on the NAS to power save but it is disabled and I am informed by the Iomega community that it doesn't work anyway. Truth to tell the situation has improved since the installation of updated firmware and for most of the time it is usable. The problem seems to be a timeout when using explorer to display thumbnails of images in particular and sometimes videos so I get around that by operating in details view which seems to work.

The second issue however is still extant, although Iomega say they have supplies signed drivers in a recent release they don't work either for me.