Again, it seems to me that it is more important for you to study grammar and vocabulary. But if you are sure.... For East End London slang, Download from the Internet:
"Only Fools and Horses" It's a series with probably at least a hundred episodes. Working class slang throughout. Warning, it will be hard to understand.
"Porridge" Classic 1970s-80s series about a man who is in prison. Quite funny, lots and lots of episodes.
"EastEnders": Soap opera about working class people in East London. There are three or four episodes every week.This series has been running since the 1980s...