Aidan O'Hara in his biography of Delia Murphy, suggests she may well have learned it from Donagh MacDonagh who published a book in the '40's which included it and several others which Delia recorded. Arrangements were usually by Arthur Darley - who accompanied Delia on several recordings. While it is possible the flow was in the other direction, O'Hara thinks it unlikely.

Regards

p.s. Must go back and check out MacDonaghs collection online.. and check out the story next time I'm in ITMA.