Susan Sheridan (24 February 1947- 9 August 2015)[1] played schoolboy Simon and Mrs Streeter in the Big Finish Doctor Who audio story The Hollows of Time.
Sheridan was best known as the original voice of Trillian in the original 1978 The Hitchhiker's Guide to the Galaxy radio series by Douglas Adams, a role later played by Sandra Dickinson in the TV adaptation. Sheridan returned to the role of Trillian in the 2004-2005 continuation of the radio series.