With the extra information of birth date Ethel Gilfoyle's birth can be narrowed down...
Ethel Watson Chorlton V:8C P:840, Q3 1905
Name: WATSON, Ethel
Registration district: Chorlton
Year of registration: 1905
Quarter of registration: Jul-Aug-Sep
Mother's maiden name: Not available before 1911 Q3
Volume no: 8C
Page no: 840
and this can be confirmed by the 1911 census return, where Ethel is found with parents and siblings...
WATSON, John Head Married M 32 1879 Bricklayer's Labourer Openshaw Manchester
WATSON, Elizabeth Wife Married 9 years F 29 1882 Openshaw Manchester
WATSON, Frederick Son Single M 8 1903 Abbey Hey West Gorton Manchester
WATSON, Florrie Daughter Single F 6 1905 Openshaw Mancehster
WATSON, Ethel Daughter F 5 1906 Openshaw Mancehster
WATSON, James Edward Son M 4 1907 Openshaw Mancehster
WATSON, Beatrice Daughter F 3 1908 Bolton Lancs
WATSON, Thomas Son M 0 1911 Bolton Lancs
RG number: RG14 Piece: 23385 Reference: RG14PN23385 RG78PN1365 RD461 SD7 ED1 SN312
Registration District: Bolton Sub District: Little Bolton Enumeration District: 1 Parish: Bolton
Address: 62 Everett Street Bolton County: Lancashire
If you get her marriage cert hopefully it will confirm John the bricklayer's labourer as her father.