I'd use aerosols. Somewhere like Halfords should be able to match the colour you want. After de-greasing, rub it down with 600 grade wet or dry used wet. Mask up then use a primer - two coats with 15 minutes between them. Leave for 24 hours. Flat with 1200 grade. First coat very light and don't worry if it doesn't cover. After 15 minutes, second coat - but again keep it light, to avoid runs. And another coat. And another.
Leave for a week. Then I'd give it a flatting down with 1200 grade being
*very* careful round any edges or high spots. Then give it two coats of clear lacquer.
The materials shouldn't cost much more than a tenner or so. Brush painting will look like what it is.
Make sure it's totally free of muck, at least in the areas you'll see. I should rub it over thoroughly with a cloth and some Hammerite (style) thinners before you paint it; work very fast with the hammerite (I'd use something called "smoothrite" instead), and don't touch it when you've finished one surface. If you can apply/let dry surface by surface, keeping the thing flat and horizontal while the paint dries, then so much the better.
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