At
http://www.historicaldirectories.org/, there is a James Whybrow, chimney sweep, at that address in 1911, 1916, 1918, 1919.
In 1901, 1904 and 1908 there was a John Pickering, also a chimney sweep, there.
now at freebmd.rootsweb.com there is a marriage in 1911, possibly of Charles A. Powell to Helena M. Whybrow, in Paddington
And children to them:
Alfred J C, 1912 (appears to have died in 1928 aged 16, in Eton district)
Helena G, 1913 (died the same year)
and another son b. in 1924 (your uncle? or a younger brother of his?)
So the photo may be of James Whybrow, your uncle's grandfather, rather than his father; or it may be of some other relative of the family.