Prideaux became a solicitor. In World War II he served with Kent Yeomanry and was awarded the T.D. and the M.C. He followed in a family tradition and was clerk of the Goldsmiths' Company from 1958.[2]
Prideaux lived at Rusper, Horsham, West Sussex. He died at the age of 85.
Prideaux married Anne Cokayne, daughter of Francis Stewart Cokayne and Dorothy Emily Probyn, on 4 February 1937.