And thankyou to you, Allan, for providing the substantive material in the first place.

Offhand, I don't see any clear relationship between this tune and  My Heart's in the Highlands;  mind you, that one has more than one melody associated with it.  The tune given in the DT (Failte na miosg) doesn't seem to have a lot in common with Air Faillirin Illirin, which (for example) Malcolm Lawson matched with the words attributed to Burns in Songs of the North (volume II, 1905).  Neither does it seem particularly to belong to the  Bonny Portmore/ My Heart's in the Highlands  tune family, but at this stage I'm probably just confusing myself!