hi guys, I need to paint my garage door, the door is metal, it is currently red in colour with a type of matt finish ( not gloss)..I am under orders from "er indoors" to paint it white, I have looked at some metal paints at toolstation & wickes..and these say that I can apply directly onto the garage door with no primer or undercoat etc..but I am not to sure about that so what is the best way to change the colour from red door to white door without making a pigs ear of the job ?...also can anyone recommend a brand of paint for doing the job ( and undercoat or primer if required ) also best way to paint the garage door roller or brush ?....many many thanks in advance