I guess I'll have to wait until I have a copy of Harker's other book and make my own mind up about what it says about the Critics Group and the tone in which it was said.

And I shall. For though I asked, politely, no evidence has been provided to me that Harker was 'snide' in this[...

This is all Harker says about the Critics in the earlier book; he's referring to the late 60s. Doesn't look snide to me.

MacColl, meanwhile, spent a considerable amount of time training singers, both at the Singers Club, and at more select gatherings of people (including the embryo Critics group), so as to carry on his methods and techniques. In public, MacColl made no serious theoretical contribution; but, fortunately, some of his training sessions were surreptitiously recorded.