I've not seen them before. I'm not the best person to ask though; I've not lived in England for 7 years now. Also my home town is this small quiet market town called Kettering, in a small quiet county Northamptonshire, right in the middle of England where nothing seems to change. It's mostly white English who live there, growing up there was maybe one black kid in my year at school so no integration problems there! In fact a few months ago the BBC had some report on their website about 'white flight' from London and Kettering was in the top 10 towns where the % of white English has increased due to the 'flight' from London and the fact you can get a direct train into St Pancras in an hour. Now I remember being back home and taking a train to Leicester and being really shocked (not in a bad racist way but just because it was so different only 20 minutes train ride away) at the ethnic differences between Kettering and Leicester but aside to that I have no real experience of immigration to England.
I just found this...
http://www.guardian.co.uk/news/datablog ... land-walesYou can see from there the vast differences across the country. My home town is 90% 'White British' where as one area, Brent in London, is only 38% 'White British'.