Guest Stars Tallulah Rose Haddon as Kitty Will Poulter as Colin Ritman Fleur Keith as Mum Jonathan Aris as Crispin Rochenda Sandall as Pippa 1st AD Asim Chaudhry as Mohan Thakur Craig Parkinson as Peter Butler Alice Lowe as Dr. Haynes Sandra Teles as Reporter A.J. Houghton as Young Stefan Fionn Whitehead as Stefan Butler Suzanne Burden as Judith Mulligan Alan Asaad as Satpal Ellie Piercy as Receptionist Laura Evelyn as Pearl Ritman Stephen Rashbrook voices Narrator Catriona Knox as Leslie Jeff Minter as Jerome F. Davies Tom McCall as Paramedic Jon-Jo Inkpen as Pax Paul Bradley as Robin