Thanks. Yes they are a metallic grey - one stage paint.  From memory, I think the colour was called Island Pearl Grey.  I basically just went to the refurb guys and looked looked at some colour cards against the car, then picked the colour I liked.  I also made a note of the colour code for future reference.  I did have to get one wheel redone a year later after curbing it, and the whole process was pretty painless due to them being able to match the colour exactly.