 Plowright made her professional debut with Glyndebourne Touring Opera in 1975 as Agathe in "Der Freischütz".She sang Donna Elvira in "Don Giovanni" and the Countess in "The Marriage of Figaro" with the Glyndebourne Touring Opera in 1976 and 1977.Also in 1975, she appeared with both Welsh National Opera and Kent Opera before making her debut with English National Opera as the Page in "Salome" in 1976.