Not the most exciting place inside, but a lovely rooftop area which not all that many people seem to know about, 2 mins walk from Old St station. If it’s packed then The Red Lion is just up the road.
G.F. Smith's permanent showroom, in Central London. Visits are by appointments only — But I would definitely recommend making the visit. All of their stocks are beautifully archived, along with example publications, and a rotating series of paper installations in both the window & basement, courtesy of Made Thought.
There are many quirky book stores in London, but I really love the selection that Daunt Books have, they often have bespoke editions which you won't find in other book stores. Also, the people that work there are so helpful and knowledgable. I can never stop myself from walking in!