Rennells previously hosted the late-night programme Nightride on BBC Radio 2 for 14 years.
Born in Canterbury, Rennells spent 25 years working as a journalist for various newspapers throughout the south of England, these included the Kentish Gazette, Eastbourne Gazette and Oxford Mail.
In November 1978 Rennells joined the national broadcaster BBC Radio 2 as presenter of the Thursday edition of the graveyard slot, he also co-hosted the Monday night programme Music from the Movies.
He left Radio 2 soon after, however he did continue to present specialist programmes for the station until 1995.
Rennells later revealed his Harmony Night programme is looking for a new home to broadcast on.