The Thomas Cubitt, Sloane Square
The draught is just right and the wine I had the last time I was there was heavenly (recommended by the waitress). There is no standing bar, but once seated it's hard to resist some of the food on the menu. I can easily say that I have enjoyed every meal there so far.
44 Elizabeth Street, Belgravia, London, SW1W 9PA
From Victoria (underground): follow the signs for Victoria Street and then the Coach Station. This should bring you to Buckingham Palace Road. Turn left and cross the road. Keep heading down the road before turning right along Elizabeth Street. Pass Victoria Coach Station and you'll find the pub on your right.