I would avoid this place especially if their "afternoon / high tea" groupon deal pops up. Service was rude and food portion are tiny like those mini-plastic foods. They charge extra for refilling the tiny jams and hot water. Macarons and cakes are mediocre, it's better to purchase cake from Longos imho. Plus, the place is tiny so booking with your voucher has to be done at least a month in advance.
If you're in the mood for macarons, I'd recommend Butter Avenue or La Bamboche. For afternoon / high tea, Windsor Arms still takes the cake! =P (note: cake may not be served at Windsor Arms as it depends on the day you go).