WOW. Just registered here as I had been tracking down projects my father (Robert Trygve Knudsen) had been involved in through the 60's and seventies. This is indeed a ZEUS, built by my father himself, and one of a few different conversions from his workshop. His other cars were the 'Christy 1' - a 30's style convertable, and a beachbuggy kit...
Where did you find this image? I am trying to buy one of his surviving cars!
All the best
Nice to hear from you and to find out who built this car.
I'm afraid I can't remember where I found the image, nor have I been able to find it again.
I surf the whole Internet looking for images just like this to post as puzzles and as long as there's some info with the picture, like its name or who built it, then it makes a good one.
So I'm afraid I can't help you, but if you have any interesting photos of your father's car then please feel free to post them!