I can tell you what Germans most miss when they are in England:
Bread (proper bread, as we say!)
German bakeries usually sell around 30 to 50 different types of bread.
Also I always used to get my mother to send me milka chocolate, until I actually found them in a shop in London.
Here I'd like to add that Ritter Sport Chocolate is NOTHING like a Kitkat.
It is a chocolate bar, similar to Cadbury'S chocolate bar, but comes in a wider variety of flavours.
While the English traditional meal is meat with two vegetables (I think), the Germans have a lot of vegetarian or mixed dishes like a type of pasta with melted cheese and fried onions or Maultaschen, which could be compared to Ravioli, but is fried with egg and onions or eaten in a clear soup.
Bavaria is famous for its Sauerkraut and spitroasted pork.
Hamburg has a famous 'leftover' dish (Labskaus), with all kind of stuff mixed into it.
What I also have not seen in England is a sausage salad, made with Lyoner Sausage, sometimes with added cheese and/or black pudding (all cut into slices, with a vinaigrette.
All over, though, I don't think the German kitchen is any more famous in other parts of the world than the British...