As these photos show, this is a Roboman helmet in the design of a 1966 Daleks Invasion Earth 2150AD. It is screen used from the filming in 1995 of the Dalekmania Documentary. It is one of only 4 used in that production. They can be seen in use in the middle of the Documentary, which is an extra on every release of the 2 Peter Cushing movies, made in the 1960s.
It was made by Dalek specialist and model/prop maker Julian Vince, whose work has been used in Doctor Who documentaries, and magazines for decades. The helmet is in used condition, and was only intended to be seen in 'longshot' during filming with the 4 Robomen, almost 30 years ago.