Depends-- later on as it becomes progressively more and more liberal we could see it become the United Kingdom of Great Britain and France, but it's contemporary name in history(Atleast for the England and the Western French fiefs it controlled) was something more or less refered to as the "Plantagenet Realm". Later, it became known as the Angevin Empire, coming from the denonym of a resident of Anjou. In the modern era, there were plans to unite France and GB in the event of France loosing in WW2 so as to prevent a French seperate peace-- this was refered to as the Franco-British Union.