Geoff Harrison has just sent me this:
"It gets more and more interesting. Simon Featherstone in his anthology ' War poetry - an introductory reader' attributes it to Pte. W. Lloyd of the 12th Sherwood's. Corporal G. E Attwood of the 2nd London Regiment had it published. ( not sure of date)
Pte John Hughes, of the Leinster regiment had 'his' poem published in the Longford Leader on 15th Jan 1916.
Pte W.J Walton also wrote it. His nephew John Walton published the ' manuscript' in a Buckingham and District newsletter. And then, finally ( for now), the National Archives have the private papers of one Thomas Moore Emmanual Ward (Ted) of the Sherwoods'. Ward was part of the group responsible for the wiper's times. The copy is a handwritten manuscript. So Lucy, the plot thickens. That's at least 8 possible sources. Geoff Harrison, 19th August 2015.
Many thanks indeed Geoff.