"because they're the best known from recent tradition"
I have never had a problem with the idea that the broadsides had an increasing influence on the repertoire as the tradition deteriorated but I still reckon the options are still open that it was orally transmitted - you made the point yourself about the similarities of the tunes, which indicates oral transmission
One of those "nobody knows - QI questions again"
Steves marathon pedlar's journey from Yarmouth to Gower seems the less likely of thecchoices.
Peter Cook's Canal, railway road workers continues to attract me and, as he was talking roughly about the same period with the Greg material, increasingly so.
It seems to me that there are a lot more questions here being avoided rather than answered - not referring to you, of course
Jim Carroll