[Arran]

Are you certain that the tuner chassis out of that Scott 16 was chrome plated? It looks pretty dull for chrome plate, as a matter of fact it looks more like cadmium plating or zinc possibly, chrome plate should look like that power supply/amp chassis before you started. Since the 16 was a sort of budget model maybe they skipped the chrome on the tuner chassis but left it on the power supply/amp since the latter was shared with other models? The good news is that if it was cadmium or zinc plated then it's much cheaper to redo since it's only one type of metal, most chrome plating such as for car bumpers is triple plated, copper, nickel, and then chrome. I have a suspicion that Scott performed what is known as "flash" plating, like what they used on cheap bicycle parts, they chrome plated the bare steel and skipped the other steps, otherwise why would the plating get spotted or rusty on something that spent it's life indoors when old car bumpers would not?
Regards
Arran