Maggs Bros (Mayfair)

Status: Still in existence (as far as we know, but not recently checked)
Address: 46 Curzon Street, Mayfair, W1J 7UH (osm) (gmap) (bingmap) (streetview)
Phone number: 020 7493 7160
Website: Website
Twitter: @MaggsBros
Notes: Rare books and manuscripts. Originally at 50 Berkeley Square, it moved to 46 Curzon Street in November 2015. In May 2017, it also opened new premises in Bloomsbury.