The song was collected by Rev. Baring Gould from a man who was working on the Burrator Reservoir at Sheepstor on Dartmoor in 1894. It has 6 verses in the original with an extra one given in the appendix of Songs of the West. The original manuscript is in Plymouth library but if you contact The Wren Trust in Okehampton, they have all of Baring Gould's Collection on microfiche, including many previously unpublished collection notebooks, and they may have variants. You could also contact Martin Graebe in Cheltenham as he knows more about the collection than anyone else on this planet...and he's a nice guy!