Sybil is listed twice in the 1901 census, but with different birth years
In the 1901 census of Canada Chambly and Vercheres, Saint-Lambert, Quebec
Head John P. Sudbury, born April 23 1852, England, age 48, immigrated 1882, insurance agent
Wife Catherine Sudbury, born December 2 1858, England, age 42, immigrated 1882
Son Wilfred J. Sudbury born April 19 1883, Quebec Province, age 17
Daughter Mildred Sudbury, born November 9 1894, Quebec Province, age 6
Daughter Sybil Sudbury, born January 10 1892, Quebec Province, age 9
and
In the 1901 census of Canada Burrard, Vancouver, British Columbia
Head Charles S. Binns, born October 27 1868, England, age 32, immigrated 1889, purser on Empress of China,
Wife Kathleen Binns, born October 10 1877, England, age 23, immigrated 1883
Sister in Law Sybil Sudbury, born January 10 1893, Quebec, age 8

Vancouver Daily World, July 28 1919
Engagements
The engagement is announced of Mr. Dare Robertson Alexander of Hornsea, East Yorkshire England and Miss Sybil Sudbury, daughter of the late James T [should be P.] Sudbury and Mrs. Sudbury of Vancouver. Miss Sudbury leaves for England by August where the marriage will take place immediately on her arrival.

In the July to September 1919 marriage index Mary S. Sudbury and Dare R. Alexander, Skirlaugh district, East Yorkshire, volume 9d, page 901

1931 Canada Census 3878 West 33rd, Vancouver South, British Columbia
Head Dare Robertson Alexander, age 44, born India, father born Scotland, immigrated 1910, mother born England, secretary - golf club
Wife Mary Sybil Alexander, age 38, born Quebec, parents born England, homemaker
Son Edward Sudbury Alexander, age 10, born England, father born India, mother born Quebec, immigrated 1923, student
Son Robert Renfrey Alexander, age 9, born England, father born India, mother born Quebec, immigrated 1923
Daughter Mildred Helen Alexander, age 4, born British Columbia, father born India, mother born Quebec
Son Donald Robertson Alexander, age 4, born British Columbia, father born India, mother born Quebec
Sister Helen Ross Thompson Alexander, single, age 47, born India, father born Scotland, mother born England, immigrated 1931, income

British Columbia Death Index
Mary Sybil Alexander, died May 29 1966, age 73, Vancouver

Findagrave.com
Mary Sybil Sudbury Alexander
Birth 10 Jan 1893, Saint-Lambert, Abitibi-Temiscamingue Region, Quebec, Canada
Death 29 May 1966 (aged 73), Vancouver, Metro Vancouver Regional District, British Columbia, Canada
Burial Ocean View Burial Park
Burnaby, Metro Vancouver Regional District, British Columbia, Canada Show Map GPS-Latitude: 49.2173528, Longitude: -123.0150833
Memorial ID 231854622
Her parents were James and Catherine Sudbury.
Obituary in The Province (Vancouver, BC), 31 May 1966, p 22.
She was a Silver Cross medal recipient.

of Hornsby, East Yorkshire

In the 1901 census 19 Marlborough Avenue, Cottingham, Sculcoates, Kingston upon Hull, Yorkshire
Head George Alexander, age 59, retired mechanical engineer, born Dundee, Scotland
Wife Lena Alexander, age 53, born Southampton, Hampshire
Son Robert Alexander, age 16, born Hull, Yorkshire
Daughter N. C. Alexander, single, age 24, born Calcutta, India
Daughter Nellie Alexander, single, age 18, born Seebpore, India
Son Dare Alexander, age 14, born Calcutta, India
Son Bertie Alexander, age 12, born Hull, Yorkshire
Visitor Lenora H. Smith, single, age 20, born Seebpore, India
1 housemaid and 1 cook

In the 1911 census of Canada 841 Georgia, Vancouver, British Columbia [Seems to be a hotel or large boarding house, as there are many boarders, some waitresses and chambermaids,. A total of 45 people]
Boarder Dare R. Alexander, single, born October 1887, India, immigrated 1910, Scotish origin, Canadian Nationality, Anglican, architect,

Canadian WWI Military Records
D. R. Alexander [later signs as Dare R. Alexander], Regimental Number 75072, A company, 29th Battalion, Private
Born Howrah, Calcutta, India, October 25 1887
Next of Kin: Angelina I. Alexander, Eastleigh, Hornsey, East Yorkshire, England
Trade, draughtsman
served in any military force? Cadet Corps, Hymers College, Hull
married: no
Oath taken November 7, 1914
Place of Enlistment, Vancouver
His pay is assigned to Miss Sudbury, 3632 - 3rd Avenue W., Vancouver, B.C.
May 20 1915 Embarked to England of RMS Missambie
September 18, 1915 Transferred to Base Details, Otterpool Camp
October 10 1915 Taken on strength 48th Battalion, Shorncliffe
October 16 1915 Commission New [Imperial] Army, struck off strength, character very good
Thus his Canadian Records end

UK WWI Pension Ledgers
Dare Robertson Alexander

Canadian Ocean Arrival, Form 30A
September 9, 1923
Dare Alexander Robertson, age 36
Married, wife Mary Sybil Alexander
Present occupation, poultry farmer, intended occupation same
Born Howrah, Calcutta, race Scotch
Citizenship British, Religion Church of England
Going to Canada to settle
Intend to remain permanently
Previous address 1078 Harwood Street, Vancouver
Port of Previous entry, Montreal August 1910
Departure from Canada Montreal May 1915
Why did you leave? Canadian Expeditionary Force
Money in Possession 500 pounds
Destined to 1078 Harwood Street, Vancouver British Columbia
Nearest relative in country from which you came, Brother R. M. Alexander, 83 Elm Park Mansions, Park Walk, Chelsea

British Columbia, Canada Death Index
Dare Robertson Alexander, died Jun 5 1968, Vancouver, age 81

Findagrave.com
Dare Robertson Alexander Veteran
Birth 25 Oct 1887, Howrah, Howrah District, West Bengal, India
Death 5 Jun 1968 (aged 80), Vancouver, Metro Vancouver Regional District, British Columbia, Canada
Burial Ocean View Burial Park
Burnaby, Metro Vancouver Regional District, British Columbia, Canada Show Map GPS-Latitude: 49.2173528, Longitude: -123.0150833
Memorial ID 234013636
His parents were George and Angelina Isabella Alexander.
Dare enlisted as a Private, Service number 75072 in the 29th Battalion, Canadian Expeditionary Force in Vancouver, British Columbia on Nov 7, 1914 and was discharged from the service on Nov 2, 1915 in Shorncliffe, England having been appointed to a Commission in the Imperial Army. He served there as a Lieutenant, British Army Service Number M77368, with the East Yorkshire Regiment.
He married Mary Sybil Sudbury on Sep 10, 1919 in Skirlaugh, Yorkshire, England.
Obituary in The Province (Vancouver, BC), 7 Jun 1968, p 32.