Jim,
I'm sorry you have gone to so much trouble. I have had the book in question for many years. I'm quite familiar with your work. I even have some copies of the ballads that were sold in this way.

We've been over this ground before. IMO what the travellers were doing in Ireland in the mid 20th century does not relate closely to the situation in southern England in the early 19thc. Most of what you describe is the case in that someone wrote a ballad and took it to the printer, got his shilling, and in most cases that was end of the matter for him until he'd written another ballad. The street sellers came to the printer, bought a batch of ballads, then sold them in the streets for a penny, often singing the song on the sheet, but not always. Now I'm sure occasionally the street singer would cash in on this extra money by keeping an ear to the ground as to what was selling well with ballads from other sellers and printers. I have never denied there was interaction between print and oral tradition in both directions. In fact I have lots of examples that didn't survive until the collectors came along. But these were all commercial transactions which was my original point.