The newest edition of Oldtimer Markt magazine has an article about that car.
The car has the chassis #1198 which was initially sold by the Bugatti dealership in Paris on July 16, 1921.
The source for Utermöhle having built the first body is the Nordic Bugatti Register, but there is no proof for it.
The puzzle picture must have been taken in 1928 or later because of the number plate. Except for that picture there is no documented history for the years between 1921 and 1935 when the car appeared in Sweden.
After the Second World War the car was taken apart, the chassis modified to an underslung and the body was scrapped.
The engine appeared later again when it was planned to mate it with a shortened T23 chassis # 1828, but that idea never materialized.
The current owner bought the engine and the 1828 chassis nine years ago. Sonn afterwards he had the chance to buy another chassis which is most probably the original 1198 chassis (the "chassis" numbers on early Bugattis weren't on the chassis, but on the crankcase). The current owner managed to get hold of other parts from car # 1198 like radiator and axles. The current body is a freestyle interpretation built in the Czech Republic.
There is no proof either that # 1198 ever raced on the Avus in Berlin.
Below a picture of the car in Sweden after 1935:
