Lamorna Cove is about 6 miles south west of Penzance - just round the coast from Mousehole (of Tom Bawcock and Starry Gazey Pie fame). I think that puts the song firmly in the Penzance area.

Mevyn Vincent always sang very similiar words to the Yetties version - perhaps someone should ask the Yetties where they got their version - they have a website somewhere.