Here is a portion of the lyric to the Alisdair Roberts song (I am not sure if they are related to the song I'm looking for?)

"As I roved out one shrovetide eve
among the bramble and the cloudberry
its then I heard a melody
a blowing over the northern sea
the song of the old men of the shells

the old men of the shells my boys
the old men of the shells
I left the ones who loved me well
to find my home in the heathery dell
and follow the old men of the shells"