>If the song came from a conquered people, it is no >surprise that its origins remain mysterious
At the time of Henry VIII Scotland was a completely independent nation, whose monarch was to succeed Henry's daughter as King of England, and England's rule only held sway in a small area around Dublin known as the Pale.
I've never heard that Anne Boleyn had an extra boob, she may have been said to have an extra teat which is quite different. Moles or other blemishes were often considered to be extra teats.
Greensleeves certainly used to be the signature tune of ice-cream vendors in England.