Banks was also understudy for the Doctor, playing him twice when Pertwee was ill.The Ultimate Adventure: Wow, what a contrast. Whereas Seven Keys to Doomsday was a solid story, this later play from 1989 was so much worse, even though they were both by Terrance Dicks. This one is overindulgent and barely coherent, and the fact that it's partly a musical doesn't help much, since the songs aren't outstanding and only the first one (performed by a singer at her work) is in any way justified. The plot theoretically involves the Daleks teaming up with the Cybermen and a band of mercenaries, but the Cybermen are a token presence, contributing nothing of note to the story. The plot is also quite dumb; the Doctor has to rescue a diplomatic envoy before a vital peace conference, and the story uses the "San Dimas Time" trope, insisting that the Doctor has a finite time to save the envoy before the conference starts, even though he's in a time machine. It's even a plot point in one sequence that the TARDIS accidentally brings the Doctor's male companion right back to the very moment when the Doctor first rescued him from execution, which directly undercuts the ticking-clock premise. Yet no explanation is ever offered for why the deadline exists. It's very lazy plotting.
Judging from the documentary feature, a lot of the problem was that the producer this time had a lot of demands for things to be put into the story so that he could use various bits of stage gimmickry like wirework flight effects and stage-magic illusions, the result being that there were a number of totally arbitrary events that were just put in as excuses for such gimmicks. It seems there was so much attention paid to the parts that not so much thought was put into the whole.
There's also a bit where Dicks outright recycles a sequence from Seven Keys, where a companion impersonates a Dalek, gets found out when they fail to give the right recognition code, and is apparently killed before it turns out they slipped out of the Dalek casing before it was blasted. It isn't even handled as well this time as the previous time.
But not all the problems come from the play. The adaptation is pretty bad too, in that it goes overboard with having the characters verbally describe every single item or location and narrate every single action, even when it's entirely evident just from the storyline and sound effects (e.g. when the Dalek Emperor orders the Daleks to fire on the TARDIS and a barrage of Dalek gunfire is heard, one of the companions yells "They're all firing at the TARDIS!"). It's annoying as hell.
The only thing that made it tolerable was Colin Baker's voice. His Doctor is always marvelous to listen to even when he doesn't have very much worthwhile to say. The play originally had Jon Pertwee reprise his role, with Baker taking over for the second half of its tour, but of course by 2008, Baker was the only option.
The other returning cast member from the play was David Banks, who played the mercenary leader. Oddly, they didn't have him play the Cyberleader, with Nicholas Briggs doing double duty as the Daleks and Cybermen. I got the sense from the interviews that Banks specifically asked not to play the Cyberleader in the original play, which was how he got the mercenary role, but it would've been nice if Big Finish could've talked him into reprising the role for old times' sake.
So now I think I'm pretty much down to The Companion Chronicles and Short Trips, before getting around to stuff like Jago & Litefoot and the other miniseries. I'm thinking maybe CC first, since I think those started earlier.
Susan after DIOE is coming out this year, with Lucy Briers taking on her mother's role as Jenny.