Causeway.

Audio  Although I've been pretty open to Audacity's presence, like C'rizz before her (or after her if you like) and other multiple companion combinations, the character has the effect of splitting the dynamic between the usual duo of leads.  Which means the writer either has the Time Lord with one of the companions or a guest star or the two companions off by themselves.  This does make the interactions between, in this case the Eighth Doctor and Charley, all the more precious (much as it would if they were split up for narrative reasons) but it also does a disservice to the third wheel companion, who rarely feels like they have agency and often ends up being a puzzle to be solved.  Often that actually resolves itself when there are three companions, although in one recent Doctor Who era that turned into two tragic blokes acting as a distraction from us seeing Thirteen and Yaz making each other happy on a weekly basis.

Lost Amongst the Stars

"Who turned out the lights?"  For a good proportion of the story's run time I was convinced the monster reveal would be the Vashta Narada and the resulting beasties feel like they could be part of the same phylogenetic tree.  As the review in this month's parish circular indicates, there are shades of Event Horizon and Alien in the grim inevitability of humanity paying the price for venturing where they probably shouldn't given all of the warning signs.  Outside of the Doctor's perspective, there is a certain element to most stories set in deep space which mimics Star Trek but almost everyone involved is wearing an imaginary red shirt.  This is a grim slice of body horror which highlights this early Doctor's pragmatism.  Even when all evidence suggests everything is lost, he continues to fight, something which is less apparent in later stories.

Causeway

As those of us who've been lost in these narrative thickets for many years know, a franchise this broad and deep is inevitably going feel repetitious and Causeway locks itself firmly in those patterns like a sailboat in a magic eye creation.  For much of the story's running time loads of it felt very familiar but not in three main genres of Doctor Who sense but something far more complicated than that.  Turns out the Causeway is an organisation which at this point in their existence are attempting time travel thanks to some technology from party unknown, almost literally dropping in their laps.  Somewhat like City of Death, the TARDIS team are drawn to their front door after their experiments have a indigestive effect on the time ship's innards.  Given this is such a recent release, let's keep things spoiler free and just say "OK, kid. This is where it gets complicated."

Yes, well, alright, this story pretty much confirms there isn't some grand narrative conspiracy, this early doors (at least in Big Finish terms) Eighth Doctor and Charley and these stories are supposed to be set between the first and second OG series which makes Audacity one of those companions who appears in an earlier narrative gap and is never mentioned again.  So we can comfortably say there are three key tranches of episodes in the Eighth Doctor era at Big Finish, with the first running from Shada through to The Girl Who Never Was, the second from Blood of the Daleks through to his ongoing adventures with Liv and Helen and then the Time War (with Time Lord Victorious its own thing just before).  All power to Paul McGann for continuing to somehow make each version of the character so distinctive, backed by his excellent writers.