For the comment about Germans being an enigma, you'd have to read the whole paragraph to see what point he's trying to make. http://books.google.de/books?id=ry8v9IwFgMgC...
Looks like the typical start to a book trying to convince you that the book you are thinking of buying will be exciting, or at least revealing.
I don't think this is an example of German ideas about what the British think of them, exactly - the examples are from English travel books. This is actually an example of Germans not getting the point - or pretending not to get the point - about the comments in the travel books. Hee hee, how funny, British people think it's odd to be nude in the sauna! Ho ho! ... Of course they do, just like you would think it was funny if you went to a country where no-one wore costumes in the swimming pool. Ha ha! British people are obsessed with cuckoo clocks! Tee hee! ... And how many Germans have photos of themselves standing by a red phone box holding a pint glass?
This is a case of books trying to make Germany sound particularly odd, as that sells well, followed by magazines trying to make the books sound even weirder, as that sells just as well.