Many thanks Sean and Gary.
Gary, I used the 'Marmite Technique', first spray the part your chosen metal colour ie steel or aluminium, let it dry, dab on some Marmite with a stiff brush or small piece of sponge, spray your part the colour it's gonna be, in my case for the Albie, Vallejo Duck Egg Green, let it dry, wash the part in warm soapy water with a soft brush, voila, the Marmite comes off leaving a chipped finish with the metal showing through the paint.
Cheers
Pete.