Vic Gammon, Roy Palmer, Ruairidh Greig.

You mention the work of these people quite rightly. Have you read any of Vic's work on broadsides? BTW his review of FSE is a few postings above this one if you'd care to read it. Roy both used and wrote about the influence of broadsides in his many books. In fact he was something of an expert on the Birmingham printed ballads. I wonder if these people thought that all broadside ballads were a load of rubbish.