Richie,
When MacColl wrote those notes he probably hadn't a decent grasp of the broadside traditon. When he uses the title 'Tavern in the Town' I would guess he's actually referring to 'Brisk Young Sailor' where the verse occurs. This is quite reasonable for someone mostly acquainted with oral versions. The 1880s/1891 student song is properly titled 'There is a tavern in the Town' from the first line.