If you like your cocktails, this is certainly the place to go. The cocktail menu is the largest I've seen, and is usefully split into different themes, from biscuits to different decades.
The London Cocktail Club has four venues across London, and they serve quirky snacks too, as well as 'proper' food. The interior is good fun, and a great place for a evening out. They get really crowded so really worth booking a seat if you can.
I myself went for a jammy dodger cocktail! (below):
Location: Goodge Street, Shaftesbury Avenue, Oxford Circus and Shoreditch
Cost: usual London prices!