Brian wrote -
Phil Tanner sang 'Henry Martin' and Sam Larner 'The Lofty Tall Ship', both excellent variants of a single song, interestingly different melodically and textually, but strongly similar as well (Cecil would have called that 'Continuity versus Variation').
It beggars belief that the song would have been known at locations 350 miles apart simply by travelling along some rural grapevine

Jim wrote -
Steves marathon pedlar's journey from Yarmouth to Gower seems the less likely of the choices

Credit where it is due to the person who suggested the song's unlikely journey, please.