I revised upwards my opinion of three of the performances. First, Troughton is not just good, he is excellent, and rather steals the show from Pertwee. He gets a lot of the best lines - there is one about confusing the anti-matter blob by letting it watch television which must surely have been an ad-lib. Second, Courtney's Brigadier, if considered as an admittedly comedic authority figure, is actually pretty decent and he also gets some good nostalgia moments - thinking that Pertwee has changed back into Troughton and framing the situation as best he can. It's not the Brigadier of The Invasion or Spearhead from Space, but we haven't really had him around for a while. And third, the music is not half as bad as I remembered; I think it has to work hard to cover for the awful monsters, but does the job.
This time round I was watching the DVD, which includes a 1993 convention interview with Jon Pertwee and a 1973 Pebble Mill interview with Patrick Troughton - who looks very nervous and ill-at-ease, either he hadn't yet developed the convention-attending skills he later displayed until the day he died, or perhaps he just wasn't feeling well. There is also the 1973 Who retrospective from Blue Peter, starting with Pertwee (as himself) driving the Whomobile into the studio and then continuing with a potted history of the show, including Peter Purves introducing himself as Steven by showing Katarina's death scene from The Daleks' Master Plan - rather OTT for Blue Peter, I thought, but presumably we have Purves' choice of clip to thank for its survival when the rest of the episode was trashed.
My copy of the DVD itself has a rather special provenance. A few months ago I noticed that several items of Who memorabilia which had been sent to Verity Lambert as courtesy copies by BBC Enterprises were being auctioned on eBay (to raise funds for cancer research), and I ended up buying this DVD and (slightly by accident) a videotape of An Unearthly Child. The latter had been watched, but Lambert (who died in late 2007) had not opened the DVD, which she must surely have received, probably unsolicited, shortly after its release in 2003. On a couple of the First Doctor DVD commentaries, she remarks that she felt very sorry about Hartnell's increasingly poor health when they were working together; watching The Three Doctors, Hartnell's last acting role before his death, would hardly have made her feel better on that score, so I am not surprised that the plastic wrapper was still sealed when I got it.