Yes, 'brief' = lawyer.

'Chav' is perhaps going out of favour a bit. From the Romany word for a boy or young man, it now means a member of the benefits culture - the girls have their hair scraped tightly back so that it doesn't get in their eyes when they're pushing a baby-buggy, which they invariably are, and the boys wear football shirts which crackle slightly and emit sparks in the dark. Their sentences (verbal, not prison) end with either 'Know what I mean?', usually rendered as 'Nah mean?' or 'Innit?' and often have a rising inflection derived from Australian soap operas. UK comedians such as the 'Little Britain' team and Catherine Tate have had a lot of fun with the concept.

Not to be confused with 'chiv' which used to be a cut-throat razor used for purposes other than shaving.