Doctor Who: The Third Doctor Adventures, Volume 7

This follows the usual format of two 2-hour stories, with one set in the UNIT era, and one in space. The difference here is that these stories feature Liz Shaw and Sarah rather than Jo Grant, with both characters played by the daughters of the original actors. Thus, for the first time, we have a story in this series that features nobody from the original show – but, honestly, if you're put off by that, you'll probably have been deterred by the earlier releases and won't have gotten this far.

The Unzal Incursion – Liz Shaw, obviously, gets the UNIT-era story in this one. As the uninspiring title indicates, it's an alien invasion plot, but it rings a few changes on the regular format. For one, the aliens don't appear in person until nearly the end, making this almost an invasion by Zoom call – but their Earthbound agents are sufficiently active up until that point that you barely notice. The story also isolates the Doctor, Liz, and the Brigadier from their usual UNIT resources and still finds plenty of time for action shoot-outs that fans of season 7 will probably love.

There are a few flaws here and there, with the Brigadier turning out to be a qualified aeroplane pilot being one of the harder ones to swallow. The presence of a female army sergeant on active combat duties, while welcome from a modern perspective, also feels out-of-place in a story that's set no later than the early ‘80s and some listeners might feel the lack of Sgt Benton in her stead. (She's also Black, but it's the TV series' all-white casting that's the discrepancy here, if you really want to go down that route). These are, however, minor points in what's generally a strong evocation of the era, helped by the ‘70s style incidental music.

By this point, Treloar and Culshaw are familiar enough to forget they aren't the original actors, and Daisy Ashford does a good job as Liz Shaw; she's not really doing an impression of her mother, but it's good that she properly gets to play the hero this time – unlike her previous appearance. There's also some subtle foreshadowing of Liz's departure, and some rather less subtle hints fitting the story in with a larger arc – all explained in a short segment after the closing music. 4.5 stars.

The Gulf – Sadie Miller had previously played Sarah Jane Smith in Big Finish's remake of Revenge of the Cybermen but this marks her debut playing the character in a fully original story. She does not, of course, sound exactly like her mother, but, at least for me, she's close enough that I soon became used to it – which is more quickly than I did to Treloar, in fact. Although Sarah Jane is better known for her partnership with the Fourth Doctor, she was arguably written as a stronger and more independent character during her initial season with the Third Doctor and, naturally, that's what we get here. (Not that one would expect otherwise in a modern story set during, say, season 13, but it's perhaps less noticeable here).

The story is a base-under-siege set on what's essentially an oil rig on a waterworld during the waning years of the Earth Empire. A small group of artists have set up a facility on the abandoned rig, giving a different dynamic to the ‘base' format than we see in most such stories. It's notable that they all happen to be women, leaving the Doctor as the only male character (indeed, almost the only man even mentioned). It's not something we're likely to have seen in the TV series but here it's not even commented on – as it should be, really.

The base-under-siege format is well-played here. We get some good worldbuilding about the base and the universe around it, which plays directly into the plot and fits in with themes often seen during the Third Doctor's run. Everyone in the tiny artist colony is hiding a secret of some kind, creating a ‘whodunnit' feel, especially given that the story opens with a mysterious death. This subplot is largely resolved by around the halfway mark as we move into something that's more about trying to escape the monster. Speaking of which, while the basic concept of the monster is nothing new, it's well done, giving us an emotional insight into all of the characters it's facing, regulars and guest stars alike. This is a strong and well-constructed story of its type that manages to fit in nicely with the Third Doctor's era despite having a theme more associated with the Second. 4.5 stars.