Yes you can..Codes bought in UK..are UK codes.
They won't work in USA.
USA codes are bought in USA and don't work in UK..
I live in the UK, and I previously bought a USA code from someone over Xbox live. That code wouldn't work as I live in the UK and the code was purchased in the USA. As you can see this guy is from the UK and so he must be selling UK codes. Do you understand ?