Roger i found the paint I was talking to you about last night, hammerite do a white spray as per the link below
http://www.amazon.co.uk/gp/aw/d/B004...ooglecouk06-21
They'll prob do it in a tin too. I know they sell it at halfords too
This paint it tough as nails and I've used it on brake calipers and brake drums in the past so a bit of rain won't touch it.