[3] Manduell was born in Johannesburg, son of Matthewman Donald Manduell, of Cumbrian origin, a "leading headmaster" at Jeppe High School for Boys who had been a Major in the Royal Field Artillery during the First World War and was awarded the Military Cross and Croix de Guerre, and Theodora (née Tharp), a physiotherapist and "inveterate lacrosse enthusiast".
He was educated at the Haileybury independent school near Hertford, then in Strasbourg, and at his father's alma mater, Jesus College, Cambridge,[5] where he read Modern Languages.
He then joined the Royal Academy of Music, where his composition teachers were William Alwyn and Sir Lennox Berkeley.
[10] He held many other offices, including as programme director of the Cheltenham Music Festival for a quarter of a century (1969–1994), and as first chairman of the European Opera Centre in Liverpool from 1997.
[15] In 2020 Divine Art issued the CD Songs for Sir John as a tribute featuring works by 16 composers from different generations.
Early pieces include the Belloc Variations for piano and orchestra, performed by soloist Renna Kellaway (his future wife), and the Trois Chansons de la Renaissance, which have been recorded.