Review of all 6 episodes:
This is a sequel to The Curse of Peladon and it suffers from being far too similar, but slightly inferior, to its predecessor. The quality of acting and dialogue are at a high enough level (as is expected as a minimum requirement in Doctor Who), it is a decent entertainment and the plot with its political aspect reflecting the UK miners strike of the 1970s is perfectly OK but it is the first couple of episodes are very much filler story level, just plodding along until it kicks into life a bit in the 3rd part then has a much stronger second half to the serial with its 4th, 5th and 6th episodes all strong, interesting and fun.
The Doctor and Sarah Jane visit Peladon about 50 years after The Doctor's previous visit. There is political strife and mysterious attacks, apparently from the creature Aggedor, that are disrupting mining operations.
It is an acceptable story but nothing of particular quality or interest compared to the usual standard of the series in the first couple of episodes until the mid serial improvement which then gets really good with the arrival of the Ice Warriors. It is in the final few episodes of the story when the action and script become much more interesting. The leader of this group of Ice Warriors is an interesting and good quality villain. Pertwee is funny and entertaining and Sarah continues to show she is the best companion of all time, even though she has a few more vulnerable scenes where she almost screams which is very unlike her usual strong, brave, calm character. There are still plenty of scenes where Sarah shows her usual gutsy persona.
Overall this is a very solid but unexceptional story in my opinion.
My ratings: Parts 1 & 2 - 7/10, Part 3 - 8/10. Parts 4, 5 & 6 - 8.5/10. Overall - 7.92/10.