I have just bought a very tidy Defender 90 XS but the previous owner fitted a rear light guard and then removed it becasue the spare wheel hit it. The guard was fitted by screwing into previous rivet holes. Those holes are now empty and I want to fit rivets in the holes but they need to be the correct Stornoway grey. Can someone please tell me what size rivets I need, do I paint them first with touch up paint and then fit them? Or do I paint them carefully after fitting? It is going to be straightforward? Can anybody help please?