You will be surprised at the number of good resturants in London (also how expensive they will be) Not sure where your hotel is located but here are some I had good meals at
mostly located in or near Mayfair (near the London Hilton) Nobu (Japanese), Titanic near Picadilly Circus and Axis in the Covent Garden theatre district and Mirabelle my favourite London restaurant.
If you like good Indian food which is hard to find here in Florida, Red Fort and a resturant with menu items you wont see anywhere else, Cafe Spice Namiste near Tower bridge.
Two others a visited a few years ago The Canteen in Chelsea Harbour and Le Tante Claire used be in the old military hospital in Chelsea but I understand is now near Harrods.
Enjoy your stay in one of my favourite cities.