Found in the pages of Action Annual 1977 along with a graphic adventure. In the text story, Katin is believed dead and buried in East Berlin. But Dredger is not one of the believers. The mission for Dredger and Breed is to be unofficial observers in an agent exchange between East and West Germany. Yet Dredger finds reasons to use some guns and it's a good thing he does.
Here are the pages I have of it.