Everyone who works at Daunt Books seems to have the answer to any question you might have, watching my large dog carefully navigate their narrow aisles is always fun too.
I spend many hours in the bookshops along this stretch, namely Henry Pordes for second hand books and new discounted titles (pile on left of photo), as well as Koenig Books for new art books with lots of great discounts in the basement. (photo right). In 2001 the rents for much of this strip were increased to align them closer to market value but thanks to public support they were reduced again. Unfortunately some bookshops still closed down; Koenig replaced the beloved Zwemmers - a real institution - but thankfully still provide great books, although others are no longer bookshops at all.
Great comic shop that stocks small press, and everything else you'd expect to find. The kids section starts at early ages and has something all the way up.