Bowen studied voice in Aberystwyth and Cambridge; he sang his first of countless Messiahs in 1954, and became a respected concert and oratorio tenor, singing primarily throughout the UK, but also in the USA, Canada, Israel, Hongkong, Singapore and many European cities.
From 1957, he sang also opera (debut as Tom Rakewell with the New Opera Company at Saddler's Wells in London): primarily contemporary opera (like Albert Herring, or King Priam by Michael Tippett, both at Covent Garden), but also Mozart (Tamino, Belmonte, Don Ottavio for the English and Welsh National Operas as well as for the Glyndebourne Touring Opera). Other than that, he sang on the British radio for 25 years.
After his career, he taught at the Royal Academy of Music in London.
Reference 1: Kutsch & Riemens; reference 2