I think i need to get an analog video synthesiser. Now. I’m just starting to investigate them, and so far have discovered that EMS [yes who make the synthi stuff] also made video synths, such as the spectre. Here is a still from one
Here is the user manual. This is what it looks like

Gavin pointed me to the audiovisualisers site, as he is also on the trail….
Next up is the Chromaton 14, an american unit made in 1977
And here is a video made on one
The investigation continues, especially as I hearing rumours about old Buchla and Fairlight video synths. Could this be one?