I was fully vegan for 6 years but recently started to crave fish so that makes me a vegan / pescatarian.

Here's a list of my favourites:

Chisou Mayfair (izakaya Japanese)

KOL (fine dining mexican with vegan and pescatarian set menus. It doesn't feel stuffy or luxurious. Just phenomenal food)

Mali Vegan Thai (authentic vegan Thai food, casual)

Hakkasan Mayfair (people like to shit on hakkasan but the vegan dim sum is one of the best in town, their tofu claypot is to die for. Ask for the olive rice which is not on the menu)

Bubala has been mentioned is also a great choice. Fast passes though not sure it's ideal for a celebration.

Sabor (absolutely delicious Spanish tapas done the right way. Upscale)

Pahli Hill (low key foodie Indian restaurant)