The song was written by Dick Farrelly, formerly a Dublin policeman, who died in 1990. As for decent recordings I'd recommend the singer to whom Farrelly passed his new song in or about 1950... Carmel Quinn (www.carmelquinn.com). It was she who made it popular in North America, when she performed it on the Arthur Godfrey Show. Her rendition is superb! (BTW... I was floored to find one of my midis playing in the background when I visited her website! 'Made my day!)
As for Dreams of Alwyn, I recall having quite a discussion with a correspondent who wanted me to sequence the tune. Believing it to be copyrighted, I was reluctant to do so, but she found references to Mr. Farrelly having based his melody on the older, traditional tune. Based on that I sequenced the tune but omitted the lyrics, which are definitely Mr. Farrelly's creation.
I've never been able to find evidence of Dreams of Alwyn since that early discussion (about five years ago) and, quite frankly, I still have doubts as to its existence.