When it was announced some years ago that Airlock (the third episode of Galaxy 4) and The Underwater Menace episode two had been recovered, the news was met with polite indifference in some quarters. Galaxy 4 and The Underwater Menace, along with The Space Pirates, have to be amongst the most unloved missing/or partly missing Doctor Who stories.

This point of view is a bad one of course, as the return of any previously missing episode should always be cherished (especially as returns have been so thin on the ground since 2013). Now that half of The Underwater Menace exists, there’s no doubt that it’s gone up in my estimation.

I mean it’s still a very silly story, but it’s nice to see moving pictures now and again ….

But before we can get back to those moving pictures, there’s still the first episode to tackle. The Tenth Planet 4 to The Underwater Menace 1 means a run of twelve consecutive episodes existing in audio form only. But looking on the positive side, we’ll never have a longer streak to “enjoy” again.

As the episode opens, Jamie’s still suffering from a mild attack of culture shock, but it’s glossed over fairly quickly (partly no doubt because he’d been hurriedly written into the script at the last minute). I’m sure the location filming would have been nice, but since we can’t see it there’s not a great deal to get the pulse racing in the first ten minutes or so (save the Doctor’s glorious unspoken wish for “prehistoric monsters”).

It’s only when the four time-travellers are captured and taken underground to what turns out to be the lost city of Atlantis that the plot begins to kick into gear.

Any time I see a collection of primitive types wearing funny hats who enjoy chanting and sacrificing people, my heart sinks a little. They will become a familiar Doctor Who sight, although it’s funny how they tend to appear in the less impressive stories (like Power of Kroll, say).

As often happens, religion gets a pretty rough ride – later it’s strongly implied that anybody who worships Amdo is both foolish and easily manipulated. Normally you’d expect then to be told that it’s best to place your faith in science. Not so in this story though, especially once you’ve met the scientist in resident …

The Doctor manages to save his friends from a grisly sacrificial death after realising that the brilliant but quite loony Professor Zaroff (Joseph Furst) now lives in Atlantis (the Doctor does this after tasting a delicious meal of plankton). Yes I know that little bit of deduction sounds thin, but you’re just going to have to accept that the plotting of this story is (ironically, given its location under the sea) less than watertight at times.

Much has been written about Furst’s performance. I’ve little to add, except to say that Zaroff’s pop-eyed madness wasn’t his normal stock in trade (check out his appearances in Armchair Theatre – A Magnum for Schneider or Callan – A Village Called G for the sort of subtle performances he normally gave).

Zaroff is cautiously pleased to welcome the Doctor as a fellow scientist and is happy to explain his plan for raising Atlantis from the bottom of the ocean. This will mean destroying the world, but that’s just an incidental point …

Episode two provides us with our earliest opportunity to see Troughton in action and he doesn’t disappoint. As Furst continues to chew any scenery within reach, Troughton is calm and subdued when playing opposite him (it’s this contrast which helps to make their scenes together so effective).

Elsewhere, Polly has regressed to a helpless damsel in distress. True, I wouldn’t fancy being turned into a Fish Person either, but she shows little of the pluck displayed throughout The Highlanders. Colin Jeavons (one of those actors never really used well by the series – this and K9 & Company are both lesser chips off the block) skulks around as Damon, a man intent on turning Polly into a little fishy.

And then there’s Peter Stephens (last seen in The Celestial Toymaker) camping it up as Lolem whilst Tom Watson, despite his silly hat, maintains an air of dignity at all times as Ramo. Catherine Howe does her best with the character of Ara but it’s really a paper-thin one. Like Tom Watson and Colin Jeavons, Noel Johnson is a good actor wasted in a nothing role (at least he’d have a chance to redeem himself later in Invasion of the Dinosaurs). P.G. Stephens and Paul Anil round off the main cast as Sean and Jacko, a couple of cheeky-chappie mineworkers who team up with Ben and Jamie in order to effect a staggeringly easy break from captivity.

Watching episodes two and three back to back, you can’t help but wonder if the story’s reputation would have been higher had episode two been the one to have initially escaped the mass purgings. It’s certainly true that episode three is pretty heavy going – with only some more of the Doctor’s disguises (he favours the gypsy look today) and the remarkable underwater ballet moves of the Fish People (to the strains of Dudley Simpson’s electronic score) standing out.

The Underwater Menace is a good early example of the way this Doctor seemingly bumbles around for a solution to any problem. First he decides that inciting the Fish People to go on strike will do the trick (although at least he’s honest enough to confess shortly afterwards that he’s not quite sure what this will achieve). The Fish People catch all the food eaten in Atlantis, so their withdrawal of labour is going to have serious consequences (since there’s no way to stop the food going rotten within hours).

Zaroff may be one of the greatest scientists the world has ever seen, but inventing a fridge or freezer was clearly beyond him.

This plan, which achieves nothing in story terms, only serves as an interlude before the Doctor then declares that Zaroff can only be stopped if they flood the lower levels of Atlantis. This appears to be a rather drastic solution to the problem (some loss of life will be inevitable) but the Doctor blithely carries on anyway.

Given this, when Ben later has to pretend that the Doctor is his prisoner, his comment to a guard (“Well, blimey, look at him. He ain’t normal, is he?”) has more than a ring of truth about it.

Polly’s at her weakest and whiniest during the second half of the story. It’s a remarkable regression for her character, but hopefully she’ll be more like her old self next time.

Zaroff’s monomania starts to get a little wearying by the final episode and it’s impossible not to heave a sigh of relief once he gets swallowed up by the sea. I’ll sum up by giving this story 3 TARDISes out of 5 (a large chunk of that is down to how entertaining episode two is – without it, the mark would have been a little lower).