 Being a mother caused a transition in work and, as a freelance radio writer, Jefferis went on to write more than 50 radio dramas and dramatised documentaries as well as serials, scientific and educational programmes.In 1953, Jefferis decided to enter the lucrative "Sydney Morning Herald" prize, given annually for an unpublished novel.Over three weeks she wrote "Contango Day", co-winner of that year's award.