The problem was they hadn't rehearsed enough numbers to do an extended set as Jeff Beck had just joined them. They were good but had to resort to virtually jamming 12 bar stuff for the last 20 minutes.
You may be right about their lack of numbers as from my memory, the Riot Squad did 3 extra numbers and the majority of the fill time was taken up by an all female group Goldie and the Gingerbreads.