UK Highland Counties Missing

Hi, I noticed recently that we took an order from Invernesshire which we thought we had excluded from an expensive overnight shipping option.  I checked and the following counties are not included in the plugin list:

Inverness
Nairnshire
Banffshire
Kincardineshire
Caithness
Sutherland
Ross and Cromarty

I’m guessing these are meant to be covered by “Highland” but it doesn’t seem to work like that.

Can you help?