I have learned this evening what you are looking for.
The man I heard singing this song, was not Martyn Travis, But in an ironic twist, I do know who Martyn Travis is.
Martyn Travis, (the surname is his "stage name" so out of respect I wont reveal his true surname) Lives Just outside Dunmore East, and is still alive and well! ironically I have played with his brother in a few casual sessions, but never knew his brothers stage name was Travis.
This at last, explains to me (and you) why it is so hugely popular around Dunmore, given the author lives local.
I don't yet know if it is based on an actual fact, but wouldn't be too hard to find this out.
Hope this is something for you to chew on. :o)