I know half the answer. But I think my artist is wrong. It was All in game. The writer is a Charles Dawes.
My mother had two cassettes in her car. Only two and one was a Cliff Richard tape. And all our holidays involved long car journeys in the UK, so I knew those songs back to front. All in the wonderful game, that we know, as love... There is a rose in Spanish Harlem... All my love...
Ah, memory lane
But I can’t remember Cliff Richard playing Glastonbury. He wasn’t the original artist.
So, a complete guess - Shirley Bassey.