Found this in the attic of my flat.
Have been able to give it a basic test and all three units seem to function.
I don't have a HiFi system to test it on, I used an old 5.1 desktop theatre system and plugged it into one of the front speaker outputs, so it isn't a prefect test at all.
It's quite large: 26.8 x 21.7 x 47.4cm