In the old T.V. series Danger UXB in episode 10 there is an AVO meter used.
Q.1. Which model is it?
Q.2. What is the location of the old power station shown?
WARNING. There are some soppy bits and some biological scenes that may offend some viewers with a weak constitution. But the series was shown on T.V. in the late 70s so can't be too shocking.
I love Judy Geeson. What a fine actress.
Clue. https://www.dailymotion.com/video/x6xjle0
Good luck,
Z.