the P.R.O.B.E. organisation); John is seen opposite Linda Lusardi in the former model's first acting role. John later appeared in two Big Finish Productions' audio dramas based on Doctor Who; Dust Breeding (2001), although playing a character other than Liz Shaw, and The Blue Tooth (2007) where, as Liz, she recounts in narrative form an adventure she once had with the Doctor and UNIT. After The Blue Tooth she played Liz in four more Companion Chronicle audio plays; Binary, The Sentinels of the New Dawn and Shadow of the Past. Her final audio play, The Last Post, which she recorded on 26 January 2012, was released after her death. Other performances After leaving Doctor Who and the birth of her first child, John appeared in the BBC drama series The Doctors playing the recurring role of Marilyn Lane for four episodes in 1971. In 1972, she appeared in the one-off BBC1 drama for the Omnibus strand, Actor, I said starring Barry Foster and Martin Jarvis, just a few weeks before appearing in the Z-Cars episode Operation Ascalon. For the next several years, John became a regular performer in BBC Radio dramas, which included appearances in Radio 4 series Afternoon Theatre, Five Morning Plays, The Monday Play, Saturday Night Theatre, Story Time and being a regular story teller on Woman's Hour. Various BBC radio productions covered in these strands were Thérèse with Vivien Merchant, Jane Eyre with Patrick Allen, How To Get Away With Murder, The Concert, New Grub Street with Robert Powell, Observations on a Jesting Man, Mr. Campion's Falcon, An Infinity of Changes and Jane Austen's Lady Susan amongst many others. John played the role of Laura Lyons in the BBC adaptation of the Sherlock Holmes story The Hound of the Baskervilles, opposite Tom Baker. The four part adventure was produced by Barry Letts. She returned to radio for Radio 3's Light in Distant Rooms. In 1987, John appeared in the BBC2 drama series A Dorothy L. Sayers Mystery: Gaudy Night as Miss Burrows. She also appeared in the BBC's adaptation of John le Carré's A Perfect Spy as Dorothy Pym. Throughout January 1988, John and her husband Geoffrey Beevers appeared in BBC Radio 4's Poetry Please. John and Beevers appeared together in an episode of Agatha Christie's Poirot titled "Problem at Sea" as Mr and Mrs Tolliver. They both had roles in the audio play Dust Breeding and