Thanks guys. There are still a few black speckles that I want to get rid of, but I'm pleased with the result.
I bought myself some Autosol metal cleaner from my local car spares shop (£3.99) and then add a few bits from Home Bargains. Scouring pads, some cloths and for some reason, a dishmatic.
Technique was apply> scrub> repeat. Occasional polish with the cloth. Overall cost was about a fiver plus elbow grease!
Afterwards I gave the car a quick wash as it looked wrong!
Well worth a try - get yours posted!
Dave