I think you may find there are two connections to this song, try them both.
You have interested me that much with this song I have just ordered "the ultimate Collection" from Amazon, I must hear it in full, having just heard snippets from various web pages.
Once I get this CD I will no doubt get the words used by Clannad. I am interested to see that the original CD (Fuaim) featured Enya, I presume this track will also.
I will advise you when I obtain my CD