Yep, it's not. It's a region of the independent country of the United Kingdom. I addressed that in the third caveat on the quiz. The only reason I put England was because it was voted number 8 on TheTopTens. So even though it is not a country I still had to put it on the quiz to match up with the list. It was hard typing it in as an answer.
I've tried using UK and it does make the United Kingdom appear, so I don't know what you are talking about. If you are talking about England then the UK isn't a standard type in for that region. UK works for United Kingdom.