It’s one of at least two slip jigs called the Humours of Whiskey so that will lead to some confusion.
Thanks very much Mr Gumby, some confusion is better than total ignorance 
as peter said, there are at least two slip jigs known as 'humours of whiskey ', so this one in the video i prefere to refere to as ‘dever the dancer’ (this being it’s second name).
you can find music sheet for it here: http://thesession.org/tunes/search?type=&mode=&q=dever+the+dancer
marin
please ignore my previous post, it isn’t dever the dancer, proper music sheet for catherine’s tune is here: http://thesession.org/tunes/1023
marin
Thank you maracirac, the Chieftains album version (posted near the bottom of that session page) seems to be closest to what Catherine is playing, although it’s her variations and ornamentation that really make it interesting. It feels like she’s just improvising around the general theme of the tune rather than sticking to any specific version.