@ISUK, @ Mithras  - thanks for some very interesting suggestions. The paler greens is where I am headed at the moment pending a final decision in  September where orange may come back ahead! Are you aware of any paler oranges than Signal Orange and Blood Orange? @Mithras  - trust me metallic does not suit the Singer vibe  - it needs to be a flat solid colour. That Aston colour is gorgeous though. here's a couple of interesting sites:

http://paintref.com/cgi-bin/colorcodedisplay.cgi?manuf=Porsche

http://www.elferclassic.de/technik/farben/plack_weiss.php