I have referred above to the possibility of confusion between the two Joseph Geoghegans, one our J B the music hall composer and the other the Galway-born choirmaster in Old Greyfriars Edinburgh. Well, a Google Books snippet of an article on Tony Pastor in 'Music Journal' 1956 shows that at least one author mixed up the two:

'Joseph B. Geohegan (sic), a native of County Galway, in the west of Ireland, wrote it ['Down in a Coal Mine']. He had migrated to Edinburgh, became a schoolteacher, and was Choirmaster at the Old Greyfriars Church there for 25 years, starting in 1857. As a sideline he wrote Music Hall songs: Cockles and Mussels, Hey! John Barleycorn . . . '

Two Joseph Geoghegans, two distinct versions of 'Cockles and Mussels' set in Dublin and London respectively, a suspicion that JBG may have composed both - hopefully we'll manage to sort the matter out eventually.