This beautiful glass fascia was captured by Brian Heppell after being revealed briefly in 2014 during the fitting of new signage at 192 Brick Lane, London E1. I have looked for S. Sadler by name in the trades section of a number of Victorian and early 20th Century street directories but nothing has come up. With the full address, courtesy of this post from the wonderful Shopfrontelegy, I will have to do another scour through the streets.
Online there is only one other specific reference, this 2002 capture by Urban75. The text accompanying the picture includes this line, which is remarkable given the changes that have happened on and around Brick Lane in the intervening 15 years.
The northern end [of Brick Lane] is still waiting to enjoy the same kind of regeneration, with some of the buildings in a parlous state.
Here are some more photos, including close-ups from Brian Heppell showing the wonderful details.