LOL that wasnt even a wind up - its MOTOROLA XD Someone has seemingly been mixing my pc usb leads with a same-shape 5 pin mobile phone usb cable. No one in this household has a motorola phone so this is odd, unless its very old. Im backing up so I cant check if the same shape external hd usb cable thats working has the same number of pins, but thats surely the cause. I have never owned a motorola mobile so the symbol on the cable didnt dawn on me at first as to what it stood for. If my hd cable has the same number of pins, then I would have imagined that the mobile one should still work though, but it looks like the problem is solved-but unless someone is swapping cables around trying to wind me up, it did work last night.
Dell XPS 13 9370 (2018) review