Hi Kim,
I know the shade you mean, unfortunately I don't think its a car colour, although worth a look in halfords.
I'm having the same problem finding a faded green.
Also I have experimented with Plastikote pink, but its too pink.
Remember the guy who built the PS Glen Sannox recently? (on Mayhem I think) He has the shade you need on her underside...maybe he could help/advise
regards
Clark