I'm getting frustrated with this one. I'm thinking about the actual designated model names - is it an XK120 or an XK120C ? Maybe it was rebodied locally after a race crash.
Ignore the above - it's a stupid question, since I have a book recording the fate of all XKC cars. I just cannot find an image of this car - it seems to be at a classic car meeting or rally of some sort, since it carries a rally plaque, and is standing next to an Edwardian landaulette of some kind. Usually , photos from these meetings finish up on Flickr or similar sites, and then onto Google Images. But there's nothing.
Is your puzzle picture from a French image site ?