i'll only be impressed when that guy does East Midlands and Stoke on Trent accents ;-) for east midlands look for videos of Brian Clough, and for Stoke, maybe try googling "Blaster bates", theres not many famous people with Stoke Accents, Robbie Williams doesn't really sound typical for stoke because he spent so much time in Manchester
My parents are from stoke but even i can't imitate the stoke accent properly
the Welsh clip sounds like South Wales to me FWIW, its a much thicker accent in the north
