This is a legitimate query. Cyril is a great folk composer, and worked out of what he knew: his masterpeice "Grey funnel Line" owed a great deal, melodically and lyrically, to Dink's Song ("If I had wings like Noah's Dove"). I wouldn't be surprised if there wasn't a bit of a trad song(or two) in "Sammy's Bar". though I can't think of possible sources at the moment. Asking Cyril himself is an excellent suggestion.