Reinhard, that's the problem. There are indeed 21 tracks but only 20 listed on the sleeve. Da Faery Reel/ De'il amang the Tailors is track 7, then comes the mystery track, followed by Spence's/Lay de at dee at 9 and Oot and In/ High road at 10.
The tune sounds like a polka or a march. I think I'll just learn it anyway!