I think it was a prototype model (alligator) by trippel eurocar,a three-seat convertible,the driver sat in the center and had an Austin engine.
Yes, it was made by Hans Trippel.
You might be right about the engine, I'm not really sure..
It was the forerunner of the Triumph-engined Amphicar.
Would you like to have stab at its date since I asked for that in the original question?
Still locked!