Exotron has Five and Peri arrive on a newly colonised planet with apparently hostile aliens; but the real problem is the colonists' robots, and the fact that the chief scientist is the military leader's ex-wife. It's a fairly standard sf setting but the cast (including guest stars John Duttine and Isla Blair) take a decent script and do it well. Very enjoyable.
I was prepared to like Urban Myths as a funny piece about the Doctor and Peri feeding the Celestial Intervention Agency an antidote to their misremembering of recent history over dinner. Then unfortunately it ends with a really stupid and offensive joke about Peri waitressing all evening, which killed any charm it might have had.
When Marc Platt is good, he is very very good; but when he is not, he is boring, and I'm afraid Valhalla is in the latter category. I don't know why it dragged - indeed, maybe it doesn't, and I was just in a bad mood; but even Susannah York as the queen of the giant termites infesting the doomed human colony on Callisto didn't really lift it for me.
By contrast, The Wishing Beast, which confronts Six and Mel with two mad old ladies and a collection of persecuted ghosts, really shouldn't work, but it does. Somehow the cast, which includes Jean Marsh as one of the mad old ladies, make Paul Magrs' script really zing. Great stuff.
The Vanity Box is a slightly humorous coda to The Wishing Beast, but the humour is based on the premise that old ladies from Salford sound a bit funny, and so does Colin Baker when he tries to imitate them. This turns out to be a rather weak premise.
The latest Companion Chronicle (though I think there's another one out this week) has Jean Marsh again as Sara Kingdom, reminiscing about her time travelling with the Doctor and Steven long ago - rather a daring choice, since we all know what happened to her. Suffice it to say that continuity is respected and Jean Marsh turns in another stunning performance of a script that surely has deliberate echoes of William Hope Hodgson's House on the Borderland.
So, I liked the two three-parters, Exotron and The Wishing Beast, much more than their accompanying single-episode stories; and Home Truths is a worthy addition to the Daleks' Master Plan narrative.