Tried out Ikkyu this evening. As you might spot from the name, it's a Japanese restaurant; it has a very varied menu with a lot of stuff I'd not seen before on it.
We had edamame, their assorted sashimi selection, two of their "set meals" (salmon teriyaki and prawn tempura), along with an order of fermented soybeans with cuttlefish. Dessert was green tea icecream with a topping of sweet red beans.
The sashimi was excellent, plenty to share between two. (Well, I say "plenty", for most people. I can eat nearly infinite quantities of sashimi, so I'd've cheerfully eaten it all myself at least twice, but that might've been considered greedy.) The set meals were basically miso soup, rice, a small amount of Japanese pickles, and the main item (the latter served on a bed of whatever that grated white stuff is that always reminds me of shredded paper).
Not completely sure about the fermented soybeans and cuttlefish. It sounded like something worth a try, and was indeed interesting but probably not a dish I'll eat twice. I found the way the fermented beans clung to one another a bit off-putting, and the taste reminded me vaguely of iced coffee; caffeine and fish don't really go together as far as my tastebuds are concerned.
Overall, very good indeed; speedy service and tasty food. The total with a couple of beers and including a 10% service charge was £56 for two, which is pretty good going for Japanese food in London (unless you're at an all-you-can-eat place or the Tokyo Diner; while I love the Diner's food, it isn't really what you'd call varied).