Cheers Barry, I found the problem eventually.
Screenshot 1 below shows a Properties dialog with a button labeled 'Change Settings' in the '
General' Tab
Screenshot 2 shows the exact same Properties dialog after clicking Change Settings, but with the button now removed, if I now click the 'Driver' tab.......
Screenshot 3 shows the buttons I need!
Microsoft are crazy.... I'm logged in as administrator but they insist I have to jump thru another hoop. Why can't they just make changes active for administrator by default? Or at the very least also put a 'Change Settings' button in the 'Driver' tab?