Try your local Service centre or Halsfords car paints selection. Not easy without it showing and difficult if it's GPR and not metal body. You could try contacting the caravan manufacturer if they are still going. If in caravan club or camping and caravan club ask them for the makers tel number. I don't think they are like cars that have the colour code on the Serial/chassis number and weights plate but check you might be lucky
Nobby
October 2008