Hi Tim, you are correct in saying that the Behan family contributed a great deal to irish literature. I would acredit McAlpine's Fusileers to Dominic but he never worked on 'the Lump'. Crookit jack is copyrighted (words only, tune adapted) by Wolf Stephens which is a pseudonym used by Dominic. Dominic wrote regarding the song, "Eamonn Sullivan, a good Republican Socialist, worked on the Hydro' Electric scheme in Inveraray, Scotland. He described the conditions under which the men worked as appalling".
Good luck for the play.