I saw him once in the mid seventies. I recall his "Farting Song" and he did a lot of routines about bodily functions. To be fair, so did Shakespeare (whom I never saw live), but but Bill definitely had the greater range in his repertoire.
I remember Dave Turner as a fine guitarist, with exemplary timing. He mainly did long monologues, to a guitar accompaniment, with virtually no singing. I think he also did a funny routine about either the Creation or Noah's Ark, which was a definite improvement on the one I had read in Genisis.
Most of what I know about Dave Turner is heresay, but the consensus was that he had disagreements with the authorities about what sort of recreational herbs should be available. Apparently, this resulted in his being unavailable for gigs from time to time. He could well be in his seventies now.