The picture is of Kevin Ayers and Mike Oldfield about to go on stage in Hyde Park.
Kevin Ayers And the Whole World: In this incarnation, Lol Coxhill, David Bedford, Mick Fincher and Mike Oldfield. Sadly Ayers, Coxhill and Bedford have passed away. Little is known about the whereabouts of Mick Fincher. Mike Oldfield lives in The Bahamas.
There’s also a nice little intro with Kevin Ayers explaining the performance.