While I agree that Le Gavroche is really special, I think that for a 30th birthday in July you would be hard pushed to better the Waterside Inn. You will be made to feel really special, food and service are really superb,and you should consider staying the night - they have lovely rooms and you have a delicious continental breakfast served in your room in the morning. Not cheap, but worth every bit of the money. If I could have my 30th again, that's where I'd go!