I think this may be Sidney's family, on the 1901 census:
Reference RG13, Piece 4717, Folio 76, Page 11
36 Thomas Street, Ryhope, Sunderland
Southren, James Head M 33 Steam Engine Maker b Sunderland
Southren, Ann Wife F 25 b Sunderland
Southren, Samuel B Son M 2 b Sunderland
Southren, Thomas C Son M 1 b Sunderland
Southren, Kate A Daughter F 3 months b Ryhope
And the births (all Sunderland district):
September qtr 1898 Southren, Samuel Barkes vol 10a, page 719
December qtr 1899 Southren, Thomas Cansfield vol 10a, page 714
March qtr 1901 Southren, Kate Adelaide vol 10a, page 684
June qtr 1905 Southren, Sidney vol 10a, page 796
And the following look like they might be worth looking at:
March qtr 1903, Southren, Lees Cansfield
March qtr 1907, Southren, Charlotte C
June qtr 1910, Southren, Sarah Cansfield
And a marriage:
March qtr 1897
Sunderland district vol 10a, page 880
Southren, James Bell
+ and on the same page +
Cansfield, Ann