Guest Stars Emily Carey as Mary Conan Doyle Diana Quick as Cecelia Weiss Emily Hampshire as Madam Korzha Jeremy Swift as Dr Henry Whitaker Thomasin Rand as Betina Hargreaves Darren Kent as Fip Lily-Rose Aslandogdu as Julia Hargreaves Tracy Spencer as Lara Emilia Forster as Helena Wood Lex Shrapnel as Mitchell Pearce Tom Canton as Paul Hargreaves Edward Akrout as Henri Harry Haynes as Officer #1