Spotify has a recording of WHEN THE MOON SHINES BRIGHT ON CHARLIE CHAPLIN, sung by Stanley Kirkby in 1915, from the album "Oh! It's a Lovely War: Songs & Sketches of the Great War, 1911-1918, Vol. 4." It has one opening verse that doesn't appear in the previously posted lyrics:

VERSE: You've sung of the boys in blue.
You've sung of their girls so true.
You've marched to the strain
Of the well-known refrain
Of "Who's Your Lady Friend?" and "Tipperary" too.
Our Tommies so brave and strong
Have sung every kind of song,
But what is the lay
They're singing today
As they go marching along?