Just to clear some puzzles - this is the small monoplace built by Jakob Keller of Switzerland. It was originally fitted with a JAP engine but later a Triumph Twin was installed. He built it to comply with 500cc F3 regulations, but was unsure of what was required and so contacted the 500 Club in the UK. Unfortunately he didn't speak English so got a friend to write the letter, a Herr Wehrlin, and the 500 Club mistakenly thought Wehrlin had built the car.
Hence there are 2 entries on a certain well-known site, one for each name.