David Collings was Vogan Consul Vorus in Revenge of The Cybermen, sharing that fun with prosthetics with Michael Wisher and Kevin Stoney. Two years later he got to play a Human space explorer, Poul in Robots of Death. Finally, in 1983, he was Mawdryn in both Human and decayed being form in Mawdryn Undead.

Poull

Mawdryn as Human

Mawdryn Mutated