On Wahrenburg Reisen this picture and the company history of Wahrenburg can be found.
A translated extract: Karl Wahrenburg returned from Russian POW-camp in 1945. No busses survived the war. In 1947 the company was restarted with 2 self build busses In 1950 a beautiful 1.5 Blitz is bought to be used for the ever increasing trips. It gets a nickname "Möve" (seagull).