Hate to point this fact out to a few posting here with regard to "nations" BUT - England AND Scotland ceased to exist as separate nations on the 1st May 1707 when the United Kingdom of Great Britain was created as one single nation. From that date you will not find a single treaty or international agreement signed on behalf of either Scotland or England with any other country in the world.

Wales ceased to be a "nation" sometime in either the late 13th or mid 16th century. It's official status has since which ever of those dates you accept been as a Principality.