For some reason (blame age and misfiring neurons) I was reminded of two things:
1) Eliza Carthy's comment on the sleeve notes to "Heat, Light & Sound" that "Stone Steps is two tunes, on opposite pages in the Sussex tune book mashed up and rearranged."
2) The Kippers' explanation of the origins of "Spencer The Wild Rover" (two pages of the family song book had stuck together, if I remember correctly).