There is a puff for the programme from the BBC here
I think the most telling bit of the whole piece, and in it's own way a perfect definition of what happened at the time, is the last paragraph.
Folk-rock entered the mainstream - Lindisfarne's Fog on the Tyne spent 54 weeks in the charts - but by the mid-1970s the genre had become a parody of itself.
I do hope it doesn't do the same again, although I do find the over mannered interpretations of traditional songs, and the appearance of the 'Folk Big Band' seems to be bit of a parody, as well as being largely self indulgent.

Giok

Good pic of DG on the page!