Guest Stars Yani Alekansandrov as Humphrey's Body Aaron Collict as Caveman Dan King as Caveman Uncredited Lolly Adefope as Boiler Room Ghost Jim Howick as John (Boiler Room Ghost) Martha Howe-Douglas as Boiler Room Ghost Laurence Rickard as Nigel (Boiler Room Ghost) Mathew Baynton as Mick (Boiler Room Ghost) Ben Willbond as Boiler Room Ghost Simon Farnaby as Boiler Room Ghost