Without wishing to start a new almost-war, I thought this little snippet from the Backlash… sorry, BBC Doctor Who web site was of interest:
Another element of the seventh season with which both Letts and Dicks had been dissatisfied was Liz Shaw. This was on the basis that the independent, self-confident scientist had little need to rely on the Doctor for explanations and so, in their eyes, failed to fulfil the basic dramatic functions of aiding plot exposition and acting as a point of audience identification. Letts therefore decided against renewing actress Caroline John’s contract for a further season and the two men set about devising a new companion for the Doctor.
Anyway, here’s a little clip of Liz Shaw in action from my third most favourite story, The Ambassadors of Death. The clip is actually an example of the current restoration work being done by Ian Levine and co, so the quality of the first half is rubbish. And I don’t mean the story.