Not Austin or Nash Healey, but there is a vague connection...
Only vague connection? Bowden designed the Healeys from 1946 until 1952,..
Exactly, that's the connection, but this car has nothing to do with Healey, because...
Sketch for the Zethrin Rennsport ?
It's (allegedly) the Zethrin Rennsport design from 1953.
This design seemed totally lost until the entrie project was offered for sale a few years ago, inclding this sketch, a scale styling model and the bones of a full-sized replica using some original components. Apparently Zethrin had held on to the remnants of his project until his death in the late 80s.