Postgate married Prudence Myers in 1957 , becoming stepfather to her three children The couple had twin boys in 1959 and another son in 1964 Prudence died in 1982 . Postgate married Prudence Myers in 1957 , becoming stepfather to her three children ( Kevan , Kerris and Krispian ) . The couple had twins in 1959 ( Stephen and Simon ) ; and another son in 1964 ( Daniel ) .