What I am after though is some advice on the current finish of the panel I am going to copy. It is poor and I am thinking that 1200 grit / 1500 grit then 2000 grit wet and dry followed by a polish will do. The part I'm moulding from does not have to look good but the surface must be nice and smooth. It wont matter if there is no paint on it lol

Whats the best way to prep for moulding? I dont want to take on filling and so sanding would be my preferred method.