Not quite sure which show this is -- I'm thinking maybe Roxy '74, as it definitely seems to be that arrangement of the song.
That's her, Elisabeth Sladen, and Nicholas Courtney all in the past year and a half -- I imagine Katy Manning's feeling a little nervous about now.
At any rate, I'm going to jump out of my original posting sequence and include one of my reviews on a Shaw-era episode: Inferno. Originally posted 2008-12-28.
Inferno, it turns out, is another great Pertwee serial that is available through Netflix (disc only, no streaming).
Essentially, it's like Mirror, Mirror, except instead of Spock with a goatee, it has Brig with an eyepatch.
It's a little long (could be one episode shorter -- he spends the entirety of the first episode in the parallel universe trying to explain to everyone that he's from a parallel universe), but really it runs at a great pace overall and has a whole lot more action than most Who from that period.
The parallel universe is used to good effect, emphasizing characters who are much different (the Brigade Leader is a coward hiding behind his gun and his rank) as well as characters who are more or less the same (the pompous Professor Stahlman, who would doom the world rather than take a blow to his ego, and the dashing Greg Sutton, who defies him), with companion Liz Shaw somewhere in-between.
The best device, IMO, is that in episode 4 or 5 the Doctor outright tells the parallel cast that they're screwed and past the point of no return and there's nothing he can do for their world, but that he can still save his own, leaving several episodes for the parallel cast to come to grips with their certain impending doom and react accordingly.
The "there are some things man wasn't meant to tamper with" premise is stale, but works well for an apocalyptic "Earth ends in fire" story -- the ending of the penultimate episode, with a wave of lava coming toward the cast, while cheesily green-screened, is a striking image.
The finale is another episode that could safely be chopped in half, but it mirrors the events of the parallel world, with slight changes, satisfyingly. The ending is vintage Third Doctor, with the Doctor and the Brigadier butting heads and then one of them forced to eat crow.
The transfer has all the usual flaws I've now come to associate with Pertwee-era serials, an often-grainy picture and occasional wavy lines. I watched one episode (3 or 4) on an SDTV and it was a lot less noticeable.
There's also a second disc with extras on it; I assume they're neat but I'm not going to bother.
All in all, classic Who; worth renting, worth buying. (It DOES help to have a cursory background knowledge of the Third Doctor's setup, that he's been exiled by the other Time Lords and trapped in 1970 London, and that at this point he's trying to fix his TARDIS so he can travel again.)