This should answer some of your questions:

[1965:] Composed by William Gillespie of Sessiaghoneil, Ballybofey, Co. Donegal, a man who is still alive (1965). Two weeks ago he assured me that Dr. Johnston of Stranorlar had the biggest and best motor-car in the area during the War of Independence. And so this very practical joke was played on him. This is one of the few incidents when the ruthlessness of the campaign in the North was tempered with a little levity. The tune is one used widely by local poets for their home-spun products. (Paddy Tunney, notes Dominic Behan, 'Easter Week and After')