It could be argued that the success of contemporary music at the Presteigne Festival is due to its promotion of composers who draw on traditional forms and tonal harmony. Perhaps, but the world of contemporary music has moved on from what some nostalgically describe as the heroic avant-garde of the 1960s and 70s.
Benjamin Britten was very precise about what constituted the official canon of his works, but, in addition to his stipulated 95 opus numbers, he composed a huge amount of occasional music.