sorry i am not very good at writing german so i will write in english. i am from London and know a few spots:
FOUR STAR GENERAL
4 CAMDEN ROAD
LONDON, NW1 9DL
four star is opposite Camden Town tube station and sell urban clothes ( also some overpriced cans MTN,Belton,Molotow.)
HQ hip hop supplies
88 Brixton Village,
Coldharbour Lane,
London, SW9 8PS
http://www.hqlondon.co.uk
best can shop in london, also sells clothes and vinyl good prices £2.50 a can. i recommend this shop.
Berwick Street, W1F
near Carnaby Street and Oxford Circus tube station, Berwick Street is all record shops, if you want vinyl new and old this is the best street in London for vinyl!
also go to Covent Garden for clothes and Southbank for skateboarding. if you want to know anything else just ask!