Susanne:That's certainly possible, and you can hear the Celtic influence in the arrangements. However, the book is so thoroughly researched, that I'm guessing Uli Otto and Eginhard Konig (sorry, no umlauts) made an effort to use authentic tunes. Also, you can't discount the close contacts between German and British soldiers during the 18th centuries and the Napoleonic wars - the King's German Legion and other units serving with the British, and Irish and Scottish mercenaries serving in any number of European armies. The authors say that the words and melody for this song are "Anonym, um 1813/14".
There's another tune on the first CD which is a German version of "Ho ro, my nut brown maiden."
Edmund