The Sword of Orion, written (and pretty much everything else) by Nicholas Briggs.
I really enjoyed this. Despite the plot not being particularly new, as the "Base Under Siege" trope is very old and tired, I still think that if executed well (which this is), so therefore clichés can be forgiven.
The pacing was slow at times, especially the first episode that came across redundant, as the story could've just begun with the Doctor and Charley arriving on the spaceship. After that, the pace does pick up.
The Eighth Doctor and Charley arrive at a human colony, hundreds of years in the future, to try and find a cure for Ramsey the Vortisaur, as it's health is declining, and after the Tardis gets picked up for scrap, the Doctor and Charley get embroiled in a plot for humans to utilise Cybermen in the stalemate war between them and the Androids.
The acting, as usual, was top notch - it's clear that Big Finish put a lot of effort into the series, but the writing wasn't the most flavourful. Whilst it was generally good, there weren't really any dialogue triumphs, and some characters did feel quite boring and annoying, namely Grash.
If anybody deserves a slap, it's him.
I unquestionably liked Deeva; she completely contrasted Grash, and she was absolutely level headed and intelligent. Although it is revealed she is an android, so it does make sense...
Ultimately, Sword of Orion is relatively forgettable, but the story is fun enough to warrant a listen to once or twice, but if you've seen a Cyberman story on a spaceship, you've seen this one.
On a tangent, whilst re-reading my review it did come across to me as a bit unfairly critical, so I do want to make the point that I did highly enjoy this, despite its flaws.
Sadly, this is one of the only Main Range Eighth Doctor stories I don't own on CD. It's just so damn expensive on ebay at the moment...