Your information may be incorrect. Doris Catherine Mitchell's mother's maiden name was Myers. Other births registered in Cardiff with that MMN were:
Joseph Wilfred Allen Mitchell (1900)
Dorothy Phyllis Mitchell (1907)
This family (including Doris, aged 5, and mother Annie, 41, a widow) were living at 3 Garth Court, Cardiff in the 1911 census.
I have Doris Catherine Mitchell DOB 2/2/1906 Married Frederick Samuel Roue B. 17/5/1905 at St Pancras London 1st quarter 1936
Father was Joseph Mitchell B. 1881 D.1933
Mother was Elizabeth Ann Price B. 1872 D.1952