Hmm, plenty of food for thought - thanks all.
Loose Rivets, have found a supply of rouge - did you use a leather pad? The hundreds of feet a minute isn't much of a problem. I made a mandrel up so that the shade is in the jaws of my Bosch drill! No sweat.
I did the 180 grit through to 1200 grit wet on the pressed steel base cover. The Autosol metal polish brought that up to a mirror finish - I had no idea that raw steel could look that good. And funnily enough, I wondered how it would stand a damp environment, so left a few drips of tapwater on it overnight, in a warm kitchen. Next morning, nothing but limescale. Do you think that the burnishing effect traps the Carbon and just doesn't let the water get a hold? Weird.
billynospares / Mark 1 / Herr Von Klinkerhoffen please fight it out between yourselves. If the rouge doesn't work I'm going with Nuvite, as it stands. Two to one.
johngreen - funny enough, I left my last bottle of Brasso at the ex's. Would certainly have tried it. Peek worked quite well in tiny areas, got the shine, but as you say, the black mess... but once cleaned off, no shine - which is why I reckon something else is in it which the metal doesn't like.
Dash & Thump. No - if it was plated - it ain't now! It had been painted externally, but raw internally. I'm thinking that it's 'Birmabright' which Land Rover used extensively post-war. Slightly corrosion resistant without anodising. Although the drawn Alu tubes making up the 'mechanism' responded beautifully to the Autosol, just the shade that doesn't.
forget. Too much money! Although, yes it is doable. But if you saw the finish I've achieved on the steel, you wouldn't even go there!
roljoe. Will try the others, and if that doesn't work, Google will be a new best friend, again.
Herr Von Klinkerhoffen. Harry Cook, left 1971 - for obvious reasons.
ps. Once I have a mirror finish - is there a best polish to slow oxidation? Was just going to use AutoGlym resin stuff, but since I have digits on keyboard...
Promise to put pics up when it's done.