Nice restaurant in London for a family?

[chipperhead]

I'm after booking a nice restaurant in London for my wife's 40th Birthday, we're also taking our 2 children (7&10).
I'm after somewhere special, we've done Claridges before which was amazing but this time looking for something slightly less formal.

If anyone has any suggestions?

Cheers

 

[chipperhead]

Thanks for all the advice, we're booked in at the Hawksmoor, looking forward to it