From the Radio Times:

5.35 Colour
Dr Who
starring Tom Baker in
Revenge of the Cybermen
A four-part story by GERRY DAVIS
Part 1: The Doctor and friends return to the Ark to recover the Tardis, but things have changed.  What is behind the space plague?
Incidental music by CAREY BLYTON
Script editor ROBERT HOLMES
Designer ROGER MURRAY-LEACH
Producer PHILIP HINCHCLIFFE
Director MICHAEL E. BRIANT