Have you compared the no. of bricks in the bottom row over the door of the picture posted against the no. of bricks in any of the images available for Chesterfield Cottages on Streetview or for sale?
Unfortunately it's difficult because 1) many cottages, including no.19 now have porch extensions, 2) the cottages are on a gradient so the number of stones between doors and windows varies as you go down the row, and 3) the builders alternated between neat rows of flint stones, and a random placement, seemingly based on which side they got out of bed each morning (visible on streetview on the side elevation of no.20)
This is best view of 19 I can find, although the door pictured in 1920 could easily have been the door on the north side of the property rather than this one: