> The Deming broadside of 1835 is considerably different and introduces new material that was either traditional or manufactured by the printer.

Certainly there's new material in the Deming text. Most obvious, as you say, are the two stanzas in which the captain confronts the crew and says the murder will be hanged if he doesn't confess and left on an island if he does. But there are others, including the two lines in which Molly/Mary sees a grave with a spade beside it, and the line "Is this the bride's bed I expected to find", both of which are echoed in later oral versions. It seems safe to say that any oral version that includes any of these elements has either been influenced by the Deming text or shares with it a common source in which these additions had already been introduced.

Equally interesting, I think, is what Deming omits. There are nine whole stanzas (4, 8, 21-23, 26-29) and several individual lines in the Roxburghe text that have no equivalent in Deming. Smaller but significant omissions are the dropping of Charles Stuart's first name (becoming "a young man named Stewart") and of the name of the Bedford. It seems most unlikely that these names, once dropped, would reappear in the ballad out of nothing, so it seems safe to say that any oral version in which they occur must derive at least partly from the old broadside version (and not just from the Deming / Forget-me-not Songster version).

There are also a number of significant differences compared with the parallel lines in the older broadside; for example "and to lewd desire", "He said that is true", and "Let me go distress'd" in the older text become "in sin's hellish paths", "He said you've guessed right", and "Let me live full of shame" in Deming. And references to the original Royal Navy context are removed: "The king wants sailors" becomes "His ship must be sailing", and Portsmouth is changed to Plymouth. The presence of one or other of these in an oral version would also be a good pointer to its being derived (at least partly) from the older broadside text or from the Deming one.