Found a version with Mary mild and Christ. Joseph left behind. The Shaw and Dreamer version, quoted above, has Joseph and his Lady, but no mention of the child.

Bruce Cockburn, in discussing the three ships, suggested (also many others) that they were the 'ships of the desert' (camels).

It is the excellent old tune that people like about the carol. The words matter little. Has anyone found other early use of the tune?