The Eighth Doctor takes notice of his companion's butt in the 2007 audio play No More Lies. "Always looking at my bum," says Lucie when the Doctor tells her to mind her backside before wandering into a confrontation with a wicked time traveller named Zimmerman. It's a time loop story but without the usual repeated scenes effect; it turns out to be a decent episode about a villain who changes.
The story begins at what feels like the end of a story--The Doctor (Paul McGann) and Lucie (Sheridan Smith) having a final confrontation with the newly introduced Zimmerman (Nigel Havers). Lucie seems to have the initiative throughout, coming up with some solutions before the Doctor several times, and benefiting from an immunity to Zimmerman's "Time Whip" because she's not a Time Lord (or Time Lady). Zimmerman escapes and then the story becomes quite different--in chasing him, the Doctor and Lucie end up at an innocent looking garden party where a much reformed and elderly Zimmerman is devoted to a wife of many years named Rachel (Julia McKenzie).
It's a nice enough story, not really filled with many surprises for Doctor Who fans, but it's fun hearing Paul McGann grudgingly express something like affection for Lucie. There's a callback to the 2001 Eighth Doctor audio play Storm Warning with the return of Vortisaurs—pterodactyl-like creatures from the Time Vortex, somewhat like the titular creatures from the Third Doctor story The Time Monster, though presumably better looking than a guy in a white suit flapping his arms (I still think the chronovore is kind of cool).