I showed this song to a lecturer from the School of Irish Studies in Liverpool, who consulted one of his colleagues. It seems the song is nonsensical, and partially obscene, (which explains why my little pocket Irish dictionary couldn't cope with it).

More interestingly, it was suggested that the song seems to be a sort of work song, similar to the "waulking songs" of the Hebrides. This category of song is very rare in Irish Gaelic, not necessarily because there were very few in the past, but rather that only a small number have been preserved out of what once may have been an extensive body of song.

If I can get hold of a translation I will add it here.