Gulliver ,I have a version in front of me[which has aline Ill stay no more on Englands shore to hear the music play],this version has no mention of dublin or the liffey.
verse 5. the sun may shine though a London fog.
I think it is more likely to be English,after all it was the English government who were using Government ships to transport people to Australia,some of the convicts may have been Irish,that doesnt make it an irish song.
most of the ships sailed out of English ports.
SONGS like Skibbereen,are definitely Irish,but I doubt if Ten Thousand miles is.Dick Miles