I also have never seen that Cream TV clip before, so thanks from me, too.
I was fortunate enough to see Cream in their first major gig at "The 6th National Jazz & Blues Festival" in 1966. Previously held in Richmond, the festival moved to the Royal Windsor Racecourse that year. Although the festival was slowly evolving from jazz towards rock, it was put on by the National Jazz Federation, which operated out of London's Marquee Club, of which I was a member back then. I got sent a handbill for the festival, which I still have. Looking through the artists, I think i must have got a Day Ticket for Sunday, 31 July (cost 12/6d or roughly 62 pence!). Cream were not listed on the handbill as Cream but under their separate individual names - Eric Clapton, Jack Bruce and Ginger Baker. I guess that the handbill was printed before they had settled on the name Cream for the group.
I thought they played three songs - in the rain, as I recall - got a huge ovation and the audience was told that, as a new group, they only had those songs. More likely, the organisers wanted to keep to the timetable. Anyway, more recently, I have found a contemporary newpaper report, which says they did four numbers - "Spoonful", "Sleepy Time", "Train Time" and "The Toad" (!). Another report says that they rehearsed for this first appearance in a church hall but I believe they also played a small club in Manchester as a warm-up gig.