From the
Radio Times:
7.35-8.00
Doctor Whostarring
Sylvester McCoywith
Bonnie Langfordin
Time and the RaniThe last of a four-part story
by PIP AND JANE BAKER
Catalyst (noun): vital substance which allows a chain of events to proceed
Countdown (noun): announcement of the last remaining seconds before something takes place
Armageddon (noun): the end of the world
The DoctorSYLVESTER MCCOY
RaniKATE O'MARA
BeyusDONALD PICKERING
MelanieBONNIE LANGFORD

UrakRICHARD GAUNTLETT
IkonaMARK GREENSTREET
FaroonWANDA VENTHAM
Special voicesPETER TUDDENHAM
JACKI WEBB
Incidental music KEFF MCCULLOCH
Lighting HENRY BARBER
Script editor ANDREW CARTMEL
Designer GEOFF POWELL
Producer JOHN NATHAN-TURNER
Director ANDREW MORGAN
★ CEEFAX SUBTITLES