There's a product called Howard's Restore-a-finish, or something like that. A lot of DIY guys have used it on water marks/rings on veneered speakers with pretty good results.
Not sure how it handles fading though. Not sure if it's in the UK either. I'd try posting on Audio Karma. Lots of guys restore vintage gear over there. I'm sure someone has taken care of faded cabinets before.
Not sure how it handles fading though. Not sure if it's in the UK either. I'd try posting on Audio Karma. Lots of guys restore vintage gear over there. I'm sure someone has taken care of faded cabinets before.