I have only Glasgow from October 8, but when you say blues tune, then it might be the usual last song before the show starts? During the 2008 and 2010
that one was ALWAYS the last song before they entered the stage and on some of the simfy 2010 recordings you can hear it in parts (few seconds), it's "Feelin' Good" from Little Junior and the Blue Flames - might be totally wrong though...
This one?
LE