[Radio Wrangler]

Get the aluminium thoroughly clean. Spray with etch primer (do not breathe, it's acidic)

Halfords used to make up aerosols to any colour you wanted to match a sample or a car colour code. But now all their places send this work out, so it's not while you wait. Woodauto in Huddersfield do do it while you wait, as aerosol or liquid in a can. One aerosol or multiples of 0.5 litre, though half a litre can be expensive - always ask first, before they mix it. Other towns will have similar trade suppliers. Usually they don't mind the occasional non-trade visitor.

For a gloss finish on most modern colours, you may need to finish with an aerosol of 'clear-over-base' lacquer.

If the box had been plastic, there are plastic primers to use instead of the etch primer.

That's how to do any colour of your choice, if the aerosols in a hobbyist car accessory shop's display rack don't meet your needs.

David