Hola Jaime,
this is the the colour plate I have. I apologize for the quality, but the picture has been grabbed with my camera because I have no scanner at home.
This plate comes from the excellent "Naval, Marine and Air Force Uniforms of World War 2" - Blandford Colour Series, from Blandford Press (1975), by Andrew Mollo and Malcom McGregor.
I think that the look of Mr. Topp was very similar to this guy. As you can see, the weared shirt is the original german version, not the british. The colour too is slightly different, it tends to the german brown rather than to the british khaki. Notice also the white cap, instead of the black version of the british variant.
This is the original description from the book:
"Germany: Sub-lieutenant (Oberleutnant zur, See), England, 1945
During the war the white cap cover came to signify the captain. On his battle dress-type working blouse he wears the German Cross in Gold, and on the left the Iron Cross 1st Class. The trousers were part of the leather suit issued to U-Boat crews."