Mark - I am just wondering mate, how with the members name like "Lucky5".
This HAS to happen on ALL days, like Friday the 13th

!!!!.
If the info unit does not recover itself in the morning, lift the bonnet and with a 10mm spanner, back of the securing nut on the clamp on the BLACK NEGATIVE terminal of the 12 volt battery.
Lift the clamp clear of the battery post and just move the clamp clear of the battery post.
Now LEAVE it disconnected o stand at the side of the battery post.
Leave it disconnected for about 20 mins.
Then, place the clamp firmly back over the battery post and tighten up the 10mm nut to secure the clamp.
Now boot up the car and try the info unit - Okay ?.
Now your your USB sockets should be working correctly again.
It's a bit like the CNT / ALT & DEL fix on a computer, for EV's !.
Oh ........ Now put the magic spanner in a safe place in the car !.
If this has failed ( I don't think it will ) then it's a call to the dealer.
If you need a 10mm spanner in a hurry, just look around for a ZS EV owner, I bet he has one in his car.
Ask me how I know

.
Good luck and let us know how you get on !.