In a brief autobiography the Canadian singer-songwriter Vera Johnson writes about her first visit to London in 1966:

"One of the people I met was Meg, the Queen of
the Street Singers. She took me out busking that first day,
singing under the arches, and it wasn't long before I lost my
voice. Meg had a strong soprano voice, beautifully clear and
resonant. (If you saw the movie Darling, I understand she was
featured at the end.)"

Would this Meg be Margaret Barry?