Malcolm,
There is a very slight similarity to the Queenstown Harbor version that I am familiar with. I can see your midi being used for Lily of the West, as it is much more like one of the tunes that I know for that song than it resembles Queenstown Harbor.
BTW, it seems to be a characteristic of Irish traditional music to use the same tune with a number of different lyrics. I have heard versions of Rosin the Bow, Boys of Kilmichael, and something else all using the same tune. I know this is also true of other contries, particularly the U.S., but it seems to be rampant among Irish singers.
--Finn