User blog comment:WonderfulAsia/Hetalia English Dub Cast Updates/@comment-2004850-20100713162410

Chart time! イギリス = Igirisu = United Kingom イングランド = Ingurando = England グレートブリテン = Gurēto Buriten = Great Britain

Now that I think about it, they can still call him Britain even then. The Revolutionary War was between the colonies and the Kingdom of Great Britain. Looks like this will all work out.