Thanks to Ard Mhacha I now have Triona's recording of this beautiful song, and I am learning it- I think I'm just about grown up enough now to sing such a beautiful, big song.

The melody is very similar to Anach Chuan (still can't see the similarity to Carrickfergus though), but significantly different, as you say. I'll get round to writing the tune out in the next few days, as it's going round and round in my head.

Triona's words are significantly different to the ones posted above by Kitten- wonder where Kitten got those words from? I'll post Triona's shortly, which is the version I remember hearing years ago:

You're like the swan love that swims the ocean,
Making motion with both your wings
And your snow-white breast would be a potion
For any Lord or for any King...

They don't write 'em like that any more!