This shower valve is about 20 years old. Can anyone with a bit more experience than me identify the brand/model? No markings visible. Distance between centre of valves: 70mm
Looks very similar to the version 1 Vado Mix valves although I'm certain its not.
Whats the issue, you've got it exposed and its 20 years old. I would just be putting a new one in and because its fairly standard you won't have an issue with something of a similar size