Thanks Lighter, that is a superb and important summary.   You and all earlier contributors take a work of national importance back further in history than sources such as NLS and Wiki.   The problem is nobody else has put it all this down, apart from on this site - so it's time a revision was made.   Some on-line sources say it's not as ancient a tune as it sounds (implying late 19th/early 20th century).   WE NOW KNOW it's at least mid-19th century - but can't find an original contemporary music manuscript with it from that period. You'd think when it was being theatrically performed and also for military bands, that somebody must have written it down.