I watched this programme, and was unimpressed with the sound mix, and if it was as badly-monitored for the performers as has been suggested, then I can understand more clearly why such a gifted guitarist as Martin Simpson seemed to have such a problem accompanying Dick on "Big Muddy".   Yes, as has been noted, DG does have a distinctly personal approach to phrasing and rhythm, but it was as though Martin Simpson could not hear what was being played by Gaughan...

Dick's own guitar was not well reproduced, despite (if I remember correctly) 2 instrument mics being used. I did wonder if the prevalence of pickups on all manner of acoustic instruments these days has lead to the decline in knowledge of how to record a completely acoustic guitar...

That is speculation on my part , and not intended as a slur or anyone's skills - I just know that what I heard was woolly and indistinct....