Yo! Sushi in London

I used to live in London a few years ago around 2008-2009. One of the affordable Sushi turnstile type restaurant is this Yo! Sushi. Unless you are wealthy as expats, business owners, corporate executives, it is really hard to come to authentic sushi restaurant in London. Even so, I would really doubt whether cost is worth of quality here. But Yo! Sushi is one of the shops for mid class or students, just as I was at that time.