Hi Wolfgang,
While searching for ancestors I came across a Louis Weltje in London after who a street name "Weltje Road"was named.
Although it's not proven he is related to my family I did some searching and found quite a lot of interesting documents in the public library of Hammersmith with the great help of the librarians there ( I think it was in 1992 if I remember well).
This Louis Weltje came from Braunschweig to London as a baker.
Many people from Hanover followed the kings George III and George IV as they originated from the house of Hanover.
I guess they liked the German traditional cooking better then the English kitchen at that time.
Below a nice article (English) which describes what can happen to you if you emigrate 
With many thanks to L.W. Cowie who wrote this article in the magazine "History Today" in 1978.
http://www.weltje.gethost.nl/louis_parent/theprinceregent.htm
Although in Dutch here's also a link to the family tree of the Louis Weltje. I guess the places and names are still giving enough info for those who wish to know.
http://www.weltje.gethost.nl/louis_parenteel-frm3.htm
The home page is http://www.weltje.gethost.nl
Hope you enjoy it.
Kind regards,
Henk Weltje