If you want sushi you want Ukai. It's delicious, it's fast, it's stylish. We have been to the Poland Street branch for several times and loved the place. Upstairs lounge is great if you are looking for a place to hang out before/after dinner. You can also eat upstairs on a long wooden dining table which can seat up to 8 people comfortably.
Downstairs offers more seating since it's the restaurant floor with a bar with shelves full of sake bottles - appetizing! Black walls, black tables and dim lights give you the feeling of dining at a night club rather than a Japanese restaurant, which is a nice break from typical dining experience.
We have experimented quite a wide range of sushi selections and my favourite was the tempura sushi. Most sushi platters consist of five pieces and they are reasonably priced. (Ranging between £2.50 and £5.00). My recommendations are the Spicy Salmon Hosomaki, Salmon Avacado Uramaki and being a cream cheese lover I also recommend the Ukai California. If you still can't decide just get the mixed platters! As for the mains, Salmon Teriyaki and Chicken Teriyaki are amazing but I'm warning you; make sure you feed yourself up with some sushi first since the portions are typical Japanese style, small and elegant - if you know what I mean.
The warm sake is great value f0r £5.00 for a 180ml bottle. I loved the whole tableware but those miniature sake cups were the best. According to their website the tableware along with some other stuff like Japanese tea and incense can now be purchased. See it for yourself: http://www.ukai.co.uk/
58 Poland Street, London
223 Portobello Road, London
39 Lavender Hill, London