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