I can't help with pre-1970 much Jude, but of course after that time the City Hall in the Toon was very much a folk club on the nights when Lindisfarne played. They represented a drift from traditional folk, of course, and have been credited with launching the second wave of folk rock in Britian (following the earlier wave by the Strawbs, Fairport Convention, etc). My friends and I used to travel relatively great distances to enjoy this 'new' music and venues included the Coatham Hotel and the Jazz Club in Redcar and Dunelm House in Durham. The 'turns' we favoured were Lindisfarne, Strawbs, Rab Noakes, Stackridge et al.

At the same time we were messing around ourselves, mostly copying the aforementioned. I was briefly in a band called Mynd with the Surgeoner brothers (Bob and Billy) who were later with Jez Lowe and the Bad Pennies, and I learned much at the feet of John Dixon with whom I shared my first flat and who ran the folk club in Chester-le-Street for a while. I hear John still gets up at the Davy Lamp on occasion.

I'm afraid we viewed traditional folkies such as The Candlelighters and Johnny Handle as a bit naff, but of course I have come to appreciate them more as the years have rolled by.

Not much help, but hopefully it will encourage others to contribute. Good luck with the project.