Shvorne Marks

 voiced several characters for the Big Finish Doctor Who audio stories and spin-offs.

The Early Adventures

 * The Dalek Occupation of Winter - Amala Vost

The Diary of River Song

 * Whodunnit? - Cissy/Thelma Sketch

Class

 * Now You Know... - Michelle

The Many Lives of Captain Jack

 * The Year After I Died - Silo Crook