PS. It looks as if the main departures from the old broadside text that are shared by the Stockton, Webb, and Findlater versions can be accounted for if their common source is the Forget-Me-Not Songster version of 1844. I've just checked it on your site. Should have done that earlier.

(It's not really surprising that an American version should turn up in Orkney, given its role in the past as a stopping point for ships going in various directions.)