I'd go back to Matthew's Kitchen - for Crouch End on a Friday evening it was very peaceful with a perfect atmosphere for a bright summer's evening.
Stay off the pizza and you'll be ok.
It is a good place. The waiter/manager told me they'd been open for three weeks and I hope they make a go of it. Covent Garden has an awful lot of crap but the Oystermen aren't involved in that scene, they cook straight up good food and serve it well at a reasonable price for the area. I hope they thrive.
There was a smattering of familiar faces in the room but the real star in this restaurant was the food.