• 
  Julian Kostov

  Luca
• 
  Sidney Cole

   Didier (1 episode, 2016)
• 
  Sonita Henry

   Daisy (1 episode, 2016)
• 
  Oliver Maltman

  (1 episode, 2016)
• 
  Kai Alexander

   Young Andrew (1 episode, 2016)
• 
  Emily Lloyd-Saini

   Vet (1 episode, 2016)
• 
  Dominic Creasey

   Young Stephen (1 episode, 2016)
• 
  Penny Downie

  Ellen

• 
  Geoffrey McGivern

  Geoff
• 
  David Mitchell

  Stephen
• 
  Robert Webb (VI)

  Andrew
• 
  Louise Brealey

  Cass
• 
  Michael Wildman

   Tom (2 episodes, 2017)
• 
  Olivia Poulet

  Alison
• 
  Matthew Holness

  Laurie

• 
  Jessica Gunning

  Jan
• 
  John Macmillan

   Julian (2 episodes, 2017)
• 
  Ruth Shaw

   Jo / ... (2 episodes, 2017)
• 
  Caius Luckyn-Malone

  Young Andrew
• 
  Sebastian Patterson

  Young Stephen
• 
  Anna Leong Brophy

   Bryony
• 
  Penny Ryder

  Wendy
• 
  Clive Francis

  Phil
• 
  Dan Mersh

  Tom
• 
  Tsion Habte

  Sally