Thanks for the point Gerd, and thanks for posting those great pictures (I can't read the text either, let alone translate it).
And thanks to you Bill for the kind words. The game changer was Reply #32, I don't think I would have ever solved this without it. I never did find any information on the truck itself, but the information that it was manufactured by a company which manufactured other machinery, and was purchased by a company which manufactured like machinery and later manufactured vehicles, put me on the trail. The examination of British WWII aerial targeting maps of major industry in Brunswick led me to MIAG, which took me to the current MIAG website where I discovered that MIAG was made up of five separate companies which merged in 1925, and that the resulting company produced electric wheeled vehicles (lift trucks, etc.) as well as WWII warplanes (hence the British targeting). Once the relationship to MIAG was confirmed, the next step was to decipher which of the original companies made the puzzle truck. Fortunately three of the companies were not located in Brunswick, and thus eliminated. Of the remaining two, AGK was formed by employees of the other, and an examination of patents led me to believe that it was more likely to be the truck manufacturer. With AGK confirmed all that was left was to decipher the brand name of the truck itself. A daunting, but in the end rewarding, task.