The Longleat Cyberman head is one of the standard versions. It is marked inside with the number "10", of the original eleven. The "ear handles" and backplate are absent, as is the internal light which would have been behind the hole at the top.

For The Tomb of the Cybermen, two of the eleven Moonbase masks - one "talker" and one standard - were modified to become the hero and stunt Cybercontroller masks. This left only one "talker" mask and eight standard Cyberman masks.

However, after the actors in The Moonbase had complained that the masks were inadequately ventilated, the heads received a small but significant modification for use on The Tomb of the Cybermen; airholes were drilled under the brow ridge and on both sides of the face.

These airholes were placed in similar circular patterns on each mask. Similar, but not identical; because the new holes were positioned by hand rather than by use of a rigid template, the exact spacing between them was unique to every mask.

It was a process of elimination. Examining all the close-up shots of Cybermen eventually led me to focus on the scene in episode three where the Controller orders Cybermats to be activated. This scene prominently features one particular Cyberman as it operates the control panel.

There are good steady shots of this mask from the front and both sides. The initial check did not reveal any obvious difference that would immediately discount it, as was the case on some other masks. Fortunately the airhole patterns are clear enough to enable detailed comparisons to be made.