Name: Bertha A Hanrahan Spouse Surname: Fraser Date of Registration: Apr-May-Jun 1915 Registration district: Chertsey Inferred County: Surrey Volume Number: 2a Page Number: 187
Getting a copy of the above marriage from the GRO office in England should at least provide you with the names of their fathers.
Gabrielle was born in the quarter ending March 1922 (mother's maiden name given as Hanrahan) in Godstone, but I don't see another registration for a twin.
Found these other children:
Charlotte & Mary (twins) registered q/e June 1916 in St. George Hanover Square, London Arthur D., registered q/e September 1919 in Godstone Margaret, registered q/e December 1921 in Barrow in Furness, Lancashire James, registered q/e December 1923 in Barrow in Furness Keith A., registered q/e September 1924 in Godstone