I am sorry to see his passing. I remember him as being dark, very tall and slim, with a certain elegance that belied his gangly stature. I remember as a member of that Argyle team who went to the old Den at Millwall in the 60's and took way their unbeaten record going back some 50 odd games. I think he would have needed to have kept his head well down as the team coach came under attack with smashed windows by the Millwall young mob supporters as it left New Cross to head home!
In terms of the Millwall game, I wondered if you may be confusing him with another Scotsman, Douggie Baird? (Both men hailed from Falkirk by the way). You certainly have it exactly right with Davie Provan when you say "dark, very tall and sliim, with a certain elegance". Whilst he didn't play in that game at Millwall he did take part in another of the most noteworthy matches in the club's history - the battle of Vale Park on 10 March 74. Steve Davey got the first red card on 17 minutes and Provan and Saxton got their's right at the end. I believe it was the first time that three men from the same time had been sent off in a Football League match.