Nice to see an interesting thread regurgitated.
Gives me a chance to correct a couple of errors.
1) McColl and Seeger definitely appeared at the Bluebell. It was before I was doing the bookings and I would put it as about 1968.
2) I see on another site that Paul Simon is listed as appearing at the Rugby in 1964. I know the club did not start until after 1966 so he cannot have done so.
Although there were not as many publications about in those days I would think someone could find the correct dates for some of the occasions mentioned at all the Hull clubs.
Doc Rowe has a full set of the local "Folk News" up to a couple of years ago.