Hi Rob,
Correct me if i'm wrong, but isn't the tank a different shade to the side panels?
well, anyway, i think 2 cans should be sufficient, also a couple of cans of primer, and one of laquer, you'd be looking at around £45 + vat + postage
i recommend their primer rather than a cheapo halfords variety, seems to go on a lot better, and the nozzles in their spray cans produce a proper spray pattern at the right pressure.
cheers