Just to add some info.
I did go back to the BL and copy out the 2 versions. The one above posted by Phil was printed in Newry in 1785 but is obviously a paraphrase of the longer version printed by Goggin of Limerick which must be earlier. So both versions predate Packie's conjectured origin. Neither version, like Robert Cinnamond's, have any mention of ploughing furrows, so most likely a later addition. If anyone is interested I could post the Goggin version.

My god, I do miss Jim!