Well, it was more process of elimination. As the picture was opening up I thought that unusual engine could mean Armstrong Siddley but the car was too small . IShamrock eliminated a Kieft with the (then) unusual Climax engine. Not an Elva so not the Elva-Butterworth. So what was left in the way of small cars with unusual engines?
But it was a blind guess in the sense that I had no idea what it looks like.
