Duchêne is best known for her work as Miss Constance Hardbroom, the strict "deputy head and potions teacher" on the popular TV series The Worst Witch. She stayed with the programme for its three-year run, and appeared in the first episode of its 2001 spinoff Weirdsister College but did not return for the second spinoff, The New Worst Witch (2005–2006). Later projects included Afterlife, a paranormal drama series, and extensive theatre work.