I've found 6 children born in Darlington between 1904-1916:
John George Douthwaite b. JUN 1904, 10a 33;
Ralph William Dowthwaite b. SEP 1904, 10a 3;
Joseph Henry Douthwaite b. SEP 1905, 10a 27;
Reginald Douthwaite b. MAR 1907, 10a 29;
Agnes M. Douthwaite b. DEC 1910, 10a 9;
Robert W. Douthwaite b. DEC 1910, 10a 36.
...No child has mother's surname Cape after 1911.
Which of these were sons/daughter of Thomas and Mahala?