Factual error: After UNIT HQ disappears, you can see a patch of grass where the UNIT HQ used to be...but just exactly how can grass grow underneath a building?
Factual error: When the inside of an apple is exposed to the air for about fifteen minutes it oxidises and goes brown, but Jo's breakfast apple goes brown by the end of the scene. (This is assuming she wasn't deliberately eating a brown apple).
Visible crew/equipment: (Ep. 2) When The Doctor, Jo, and Dr. Tyler are taken into Omega's palace, in the first shot of the multiple passageways (right before Jo says that it looks like Aladdin's cave) the curved chalk actor's mark is visible on the floor, then we see it again in three following shots. Note that when they're all escorted further inside, just as Dr. Tyler comments about the matter/anti-matter not making sense, Jon Pertwee looks down, presumably to make sure he hits his mark.
The Doctor: This is a situation that requires tact and finesse. Fortunately, I am blessed with both.
Planet of the Spiders - S11-E5
Trivia: The first thing the Third Doctor does on-screen is collapse out of the TARDIS, which is also the last thing he does in that incarnation.
Question: I wanted to know what was the name of the episode where these cancerous creatures suck the bones out of you and turn you into a pile of mush - it was one of the first episodes I think.
Answer: I don't think this was a Doctor Who story. It sounds more like the 1966 film "Island of Terror" (although it did star Peter Cushing who played Dr Who in two Dalek movies around the same time).
Answer: Your right it is, "Island of Terror."