In Another Time Another Place, the instrument that Regina uses to hit the mirror (and Mathias) comes from Helena's desk. Helena also has it on the planet in The Testament of Arkadia.
In Space Brain, it is on the lab bench in Technical Section.
This is a 1959 Utility Geiger Counter Kit by Radiation Monitors Ltd of Tottenham Court Road, London (see radiomuseum.org). "Made under licence from the UK Atomic Energy Authority". It is 76 x 229 x 152mm (3 x 9 x 6 inches) and weighs 1.25kg.
It has also been used extensively in British films and television, including The Saint, The Baron and Department S. It is possibly the exact same prop, rented from a studio prop department.
Thanks to Kit Bevan and Chris Bentley's book The Vault (2022)
It appears in the 1959 ITC series The Four Just Men episode "The Deadly Capsule" (aired ATV Midlands 19 November 1959), with star Dan Dailey using it to find a missing radioactive capsule.
Here it is, held by John Saxon investigating a meteorite, in the 1965 black and white movie The Night Caller, which had several alternative titles including Night Caller from Outer Space. It was also in another black and white movie Invasion (1965), held by solders investigating the fiery crash-landing of the alien spaceship. Nick Tate's father, John Tate, appears in this film.
Peter Cushing holds it to examine the alien "silicates" in the 1966 colour film Island of Terror. Barry Gray did the musical effects.
The same instrument is used with another meteorite in the 1967 film They Came from Beyond Space, just before the scientists are taken over by the alien intelligence (two are seen). The same film also features Ludak Pesek's astronomy prints, which may be the same props seen in Victor's quarters
Copyright Martin Willey. Thanks to Kit Bevan, Chris Bentley and Simon Rhodes