Thanks all for your input. It looks like the drive is failing ( see attatched pic). Lord Xeb, I've been through all that, and it just fails to complete and the disk disappears from the window or console. Tried copying over a 1Gb video file, and it struggled to do that!
Thanks kokosnh, but it does apear to be a legit drive
And thanks WereCatf for your help, It was 50/50 fake or duff, turns out it was a duffer.
Now I gotta let the seller know I'm not a happy bunny...