Hmmm.... One thing that is puzzling me is the repeated references to "mid-Atlantic" accents. Does this mean English people trying to sound American and coming out halfway between English and American (and hence in the middle of the Atlantic?) I ask because here in the US, mid-Atlantic refers to the east coast states starting south of New England. The census bureau includes New York, New Jersey and Pennsylvania in this region, while other organizations such as the Mid-Atlantic Folklife Association include Delaware, Maryland and Virginia as well.

Needless to say, the US accent aimed for by most folksingers is either a southern accent a la Carter Family, or a Western one a la Woody Guthrie, not a mid-Atlantic one. (Dylan himself was a midwesterner attempting a more rural Western accent, a la Woody.)