First up is the English-Russian Soho restaurant Bob Bob Ricard, because if the "press for Champagne" button* isn't on your life bucket list, it should be. Feel free to get glammed up for this one, but you'll see a range of attire if you want to keep it midrange.
We made reservations for dinner, which was delicious, but you could also just go for fancy nibbles and bubbly midday. It's also worth noting that the night we went also happened to be my husband's birthday, and they brought out a glittery pink cheesecake that was almost too pretty to eat.
*And yes, the button works (all in the name of journalism).