Revealing: When Lytton stabs the Cybercontroller, some of the Cybercontroller's 'blood' gets splashed on the camera. (The 'blood' is green-dyed water spraying from the Cybercontroller's arm.).

Plot hole: The junkyard at 76 Totters Lane seen in 'Attack of the Cybermen' was also in 'An Unearthly Child'. If you consider London's high land value, it is highly unlikely that an ownerless junkyard would still survive twenty-two years....the local authority would have long since issued a "compulsory purchase order."