Bonnie Lass of Fyvie???? I don't think the song it was based on 'Pretty Peggy of Derby' was even that old. There are no versions of BLOF older than c1820 when it was written.

There are lots of ballads from that historical period that went into oral tradition but very few actually about the war itself that did. Of course there are lots of broadside ballads concerning the war. You would find them on the University of California's English ballads website in the Pepys/Roxburghe/Crawford etc. collections. This is the most comprehensive site where you would find such ballads.