Time Out says
This third London venue from the small cocktail bar group (there are others are in Soho and Camden, plus another down in Brighton) is located in the basement under the James Cochran EC3 restaurant. Expect a '20s theme and the usual bring-your-own-cocktail formula.
That means guests bring a bottle of alcohol and pay £30 on arrival for the BYOC mixologists to create original and bespoke cocktails, using their own syrups, bitters, mixers, cordials and fruits. Each booking lasts for two hours.