Not to get rockist and move away from singers but Jerry Donahue can fuckin play. Technicolour harmonics and octave transitions. Ripple clarity and never saccharine. That’s about as deep as I can go with Denny. Steeleye Span get more plays unless certain company arrives, gets drunk and stages a tune coup
The Beat Club was a German tv music thing that caught dozens of good acts either side of 1970. Fotheringay’s set in its entirety was up until a few month back. Good channel for sheer variety of archiving
I think Rob Young's Electric Eden might have some info (vaguely recall that might have been the time of the Fairport Convention van crash but could be imagining that), all I know is it's a genuinely eerie image.