That's part of the problem: there is no photo of the car. All we have to go on is a description. Here's what he said:
It was dark green and black, very low-slung, obviously from the late-20s early-30s era. A two door coupe with a passenger compartment reminiscent of a chopped Ford 3-window '32 Coupe, boattail rear, large wire wheels, and a long hood bedecked with what looked like something that may've been a Bentley Flying-B hood emblem - but on that I can't be sure, as it passed by so quickly.
In addition, there was no spare mounted on the back and, as it was a boat-tail, the passenger compartment was mounted forward, yet it still had a long hood. I posted a bunch of images that met some of his description to get a sense of proportion. He said that the closest ones were the following Ruxton (but the front end was wrong) and Bentley (but the rear end is wrong)
It has occurred to me that it may not have been a fixed head coupe, so keep that in mind too.