Peter Hill has provided this information:

Martin Muncaster has died. He was 89. For four years in the sixties he presented South at Six on TV (now South Today) from Southampton, covering the BBC southern region.
He later became a Home Service and Radio 4 newsreader and presentation announcer. He had a deep, mellifluous voice that made him  easy to listen to. He also made several films and videos through his own company for commercial clients.
He was educated at Stowe school, and in the 50s, did his National Service in the Royal Navy and became an officer.
He lived near Petersfield in the village of Steep with his son Oliver. Martin was the son of a well-known artist, Claude Muncaster.
Martin published an autobiography, ‘The Voice, The Face’ (pub. Austin Macauley) in 2021.
He enjoyed sailing and fly-fishing, and was a regular commentator at game fairs.