Sorry, no clue (which is what a lot of people say about me).

Warning: Thread drift
I thought the score for "The Watercress Girl" was available online, but poking about now, I can't locate it, meaning I probably never found it to begin with. I have a recording by John Kirkpatrick on "A Short History of JK"--track originally from Umps and Dumps: The Moon's in a Fit--and that's how I learned it. Kirkpatrick got it from John Tams (with Umps and Dumps at the time), who got it from Roy Palmer, who collected it from a West Midlands singer, George Dunn. Harry Cox also sang it. See Zierke's entry for more info. There are a couple broadsides of the lyrics at the Bodley ballads site. I'm surprised not to find the lyrics in any of the songsters at Google Books--this song is more elusive than I thought!