Sorry to put a cat among the pigeons but I've heard from couple of people that Yo Sushi isn't so good for sushi though it can be fun if you don't mind crowds . There are some lovely sushi places on and around Brewer Street in Soho- Ten Ten Tei is excellent and Kulu Kulu is great if you fancy somewhere with a conveyor belt. There are loads of suggestions here too.
yo Sushi in poland Street, opp opening of d;Arbaly Street. There is a bar in basement called Yo Below with music, all wwaiters etc have to be able to sing and sometimes just do a number then back to the DJ, they do the odd free hand massage, and have smoke exuding ashtrays.
Yo Sushi on ground floor, can get pricy as food just comes round on belt in front of you and you take what you fancy. They charge you depending on the colour of the plates you are left with. Green plates are one price, yellow plates another etc.
I know exactly what you mean, charliepops. Not pregnant so have sent my dh out in the hail to get us a box from Ichi Riki. (In Victoria and v good, froot, if you want to travel a bit. No conveyor belt tho) Sorry to rub it in...