Joe: The Traditional Balad Index is a bit off. The Hannoverian princes left the picture after 1866, when Prussia annexed Hannover. It lost its direct union with England in or about 1830, when the King's brother, Ernst August, was sent off to rule Hannover. The London Times hailed his departure, describing Ernst August as "a man guilty of every crime but suicide." On arrival, he promptly abolished red tape, red military uniforms, and the Hannoverian constitution.

But for the life of me, I cannot think of a single war between 1714 and 1939 that would have caused English or Scottish soldiers to fight in Germany. It was much easier to use German proxy soldiers. So perhaps the date of the song might not correspond to the date of the events it describes.