It is indeed a Kroboth Allwetterroller of 1954.
Manufacturer was Fahrzeug-und Maschinenbau Gustav Kroboth, of Seestall uber Landsberg, Germany who built around 55 cars from his little factory between 1954-1955. A four-wheeler with a Sachs 174cc was also built.
Well done Studhamsmudger - another point for you.
Carnut - Gustav Kroboth, stavba motoru a vozidel 'Favorit' of Sternbek, Czechoslvakia (the same man) also built simple two-seaters in that country between 1931-1932. Around 150 cars were built.
After 1945 he moved to Bavaria where he produced the subject of this puzzle - the "all-weather runabout".
Better luck next time Carnut.