An archived version of BBC Cymru has a lesson based on the song, available here. Sadly the recording of the late Meredydd Evans that accompanied it is no longer available, nor can I find it online.
I also spotted fragments of this song on a digitised page of Y Darian (Welsh-language newspaper) from 1915 in the children's column.
The final verse in the English and Welsh differ quite a bit. The Welsh is rather more down-to-earth.
"O Mari, summer's come, Tonight's a fine night, Will you come with me to walk From here to Taff's Well?"