Listening to clips on Youtube from other shows, I'm not certain they did play Pig Town Blues.
I think the slide blues stuff I'm remembering was just an extended first half of Gravel Road. And the nothing in the lyrics of Pig Town Blues sounds at all like what I remember from the new song Neil introduced.
8/5 Blaze Bayley
18/5 Flotsam And Jetsam
25/5 Gov't Mule
29/5 Dylan Moran