Genesis of the Daleks - S12-E4
Deliberate mistake: Chief of Security Nyder wears an iron cross on his uniform which mysteriously disappears in episode 3 - apparently the producers felt it was too close a reference to Nazism so it was removed from the show. (Source: DVD commentary).
Revenge of the Cybermen - S12-E5
Plot hole: The Vogans live on a planet made of gold. They helped develop the gold weapons that defeated the Cybermen. They know the Cybermen are coming and live in a state of paranoia about that eventuality. So why in the world do they attack the Cybermen with useless projectile weapons instead of "glitter guns" or some other gold-based weapon?
Revenge of the Cybermen - S12-E5
Visible crew/equipment: Quite a few times during this story arc you can see Vogans without their gold eye make-up so you can see human coloured eyelids when the rest of them is all brown.
Revenge of the Cybermen - S12-E5
Continuity mistake: The use of gold against the Cybermen is wildly inconsistent in this episode. It is said that it suffocates them. Yet Cyberman have been seen functioning perfectly in vacuum ("The Moonbase" and "The Wheel in Space"), it affects the Cybermats, who are little more than metal drones, and it affects the Cybermen's radar, which does not breathe.
Revenge of the Cybermen - S12-E5
Continuity mistake: At the end of "Genesis of the Daleks", the Doctor was wearing his big brown overcoat. However, at the beginning of this episode, he is wearing his red jacket again.
Revenge of the Cybermen - S12-E5
Revealing mistake: At the climax of episode four, the Beacon plunges close to Voga and orbits very fast before the Doctor manages to break free. The planetscape that appears on the screen is quite obviously a revolving drum with bits of clay on it.
Revenge of the Cybermen - S12-E5
Plot hole: Sarah is transmatted down to Voga after being injected with alien poison by a Cybermat. According to the Doctor, the transmat will recognise Sarah's human molecules and separate and reject the (non-human) poison molecules. As clothing fabrics tend to made of non-human molecules, how come Sarah and Harry didn't arrive on Voga stark naked?
Revenge of the Cybermen - S12-E5
Other mistake: Shortly after the Doctor makes his speech to the Cybermen about how pathetic they are, you can see a Cyberman's head wobble.
Revenge of the Cybermen - S12-E5
Continuity mistake: For a supposedly emotionless creature, the Cyberleader is easily provoked to a fit of rage, including throwing the Doctor around the Beacon.
Revealing mistake: In episode four, when Caber breaks a piece off the Zygon equipment, the entire wall shakes.
Revealing mistake: In episode four, when Vishinsky and Sarah go into the storage room to get the force field generators, the plaque on the door flops around like the cardboard that it is.
Visible crew/equipment: In episode 4, look out for the legendary "Hand of Sutekh" - a hand (presumably that of a member of the crew) holding the cushion down in the scene where Sutekh stands up.
Visible crew/equipment: In episode four, after Marcus opens the second door in the pyramid (the one with the hidden switch), someone wearing a white shirt can be seen through the opening.
Revealing mistake: The "crystal" tube holding Sarah wobbles whenever it is touched.
Continuity mistake: When Sarah Jane is sitting on the floor inside the transparent tube and the two gold-trimmed mummies/guardians appear in the background, you can see the dust on the surface of the tube change noticeably as the fade occurs.
Plot hole: It is never explained why so much of the story takes place in England. All of the equipment for Sutekh's rocket comes from his tomb and could just as easily - probably more easily - have been set up right there in Egypt. And at the end, instead of just walking out of his tomb, he takes the spatial corridor to England just so he can get caught in the Doctor's trap.
Factual error: The Doctor states that the radio waves take two minutes to get from Mars to Earth. The time interval can vary dramatically depending on where the two planets are in their orbit. But at absolute closest approach, Mars is just over three light minutes from Earth.
Continuity mistake: In the first minute of episode three, one of the evil robot mummies attacks Sarah Jane Smith. In doing so, it lunges forward, misses Sarah Jane, and smashes the "Marconiscope" device, which explodes in flames. However, seconds later, the 'Marconiscope' device is still visible in the next shot, but totally undamaged.
Plot hole: Why is the warning about Sutekh broadcast in English? (It clearly is as the Doctor identifies three E's in the transcript).
Continuity mistake: In episode 3, when the Doctor leaves the old house to find the dynamite, you can see his hat resting on a chair as he walks out the door. Immediately afterwards you see him walking through the woods with Sarah, and see that the hat has magically relocated itself to being back on his head again. And when he eventually gets back to the cottage, the hat is there, still in the chair as if nothing had happened.
Answer: Your right it is, "Island of Terror."