Philippa's post of May 23, 2002, gives a set of lyrics a little bit different than the lyrics that are largely discussed in the other posts on this thread.

These verses are sung by Máire Ní Scolaí on one of the RTÉ studio recordings re-released by the Gael Linn label on a 1971 long-playing vinyl album (named for the singer). She includes a verse which I don't see here, for which I can't supply the Gaelic lyrics.
"Seoithín Seothó" is the title assigned to the Ní Scolaí performance, rather than Philippa's title of "[ar] M[h]ullach a' tSí."

I cannot comment with a comparison of the music, as I have only heard the Ní Scolaí recording and none of the other singers' versions.

"Seoithín Seothó" may now be heard on compact disc (Máire Ní Scolaí) on the Gael Linn anthology, "Amhráin Ghrá."