[autoavia]

Thanks Autoavia,

The link was very interesting, and confirmed an earlier result I had found regarding California Sage metallic green for the "project " cars.  Still haven't a clue as to where to find a spray can similar, but will trawl the net this afternoon.  I did come up with an exact match, but it was for airbrushing, which I don't do!!

Perhaps it would simply be easier not to paint it green, but to paint it red.  That way there would be no debate as to it being an incorrect shade of green.  Let's do Ferrari red, that should be simple, shouldn't it?
Only joking

 
 Paints4u  https://www.paints4u.com/  will make you up an aerosol. Phil Smith from Scale Slot Cars and other scratchbuilders use them a lot. Not as cheap as Halfords but if you want a non standard colour to have to pay a bit extra.

 you don't have to go with Green
http://mimodels.com/catalog/product_info...ts_id=2193

or the Rob Walker car
http://mimodels.com/catalog/product_info...ts_id=1089

or http://www.mimodels.com/catalog/product_...ts_id=1088

or this one https://www.racingsportscars.com/photo/1...16-019.jpg

The Rob Walker car also ran at Goodwood and there may be one or two other colour schemes if you dig really deep.
Incidentally the first of the continuation cars was painted Red for the launch.