One of my customers sent me a nasty letter from a customer who complained that he cannot find his region (or county in UK). None of us has there probably ever been but that's a fact that they still place orders and they trust OpenCart.
Please add Channel Islands into UK zone. Apparently people do use British postcodes out there.
I also sent this issue to one of my friends who has got "Lord" title - not "Mr." and he used to be in parliament, so I reckon he knows what he is talking about. This is quote from his email:... it was not until the early 1990s that the islands joined the UK's postcode system, Jersey postcodes using the initials JE and Guernsey using GY ... http://en.wikipedia.org/wiki/Channel_Islands
Actually, it is an independently governed state but it has the same postal charges from the UK as any other place. So just pop it in as a normal option for the UK - definitely Not France. You will offend them.