Hello, thanks for your reply.
It's not my system, it's owned by the theatre I am working at and is a mac built specifically as a catalyst server (with the dongle inside the tower, etc...) It's only used for running shows so it's never been an everyday use kind of machine as far as I know.
I will try putting all of the fonts you have attached onto the system and see if it solves the problem. I did see photoshop was installed on it, but other than that I am not sure.
Cheers
A