Hi Dave,

By the looks of the image you provided, It seems to indicate that your drive is connected and able to make communication with the guest.

I could only ask, have you been able to check under VM > Settings or Ctrl + D, that those desired devices are indeed connected.

The image above should have a blue tick on the Connected check box.

Another random question,
Is the virtual machine a fresh install or perhaps a new install of ubuntu host?

if that is the case, then this link could provide answers to you:
Move a Virtual Machine to a New Location or Host 

I hope you come right.