From the Radio Times:

5.50 Colour
Dr Who
starring
Jon Pertwee
The Mutants
A six-part story
by BOB BAKER
and DAVE MARTIN
Part 3
The Doctor searches for Jo in the caves of Solos.  In the shadows the mutants prepare to attack.
Title music by RON GRAINER
and the BBC RADIOPHONIC WORKSHOP
Incidental music by TRISTRAM CARY
Script editor TERRANCE DICKS
Designer JEREMY BEAR
Producer BARRY LETTS
Director CHRISTOPHER BARRY