With reference to Bruce Olsen's post at the start of this thread, here is the link to his website which is now on Mudcat (quick links)

The Highlanders Farewell to Bonny Portmore

The original ballad, "The Highlander's Farewell to Bonny Portmore", no later then the 1740's, with both the Irish and Scots tunes, and some notes, is in the Scarce Songs 1

The song is from a Scots manuscript collection of English, Irish and mostly Scots songs, c 1740-50 (binding obscures some text).