His birth index:

First name(s) ROBERT GLOVER COOK
Last name FLOWER
Birth year 1860
Birth quarter 2
District Erpingham
County Norfolk
Country England
Volume 4B
Page 56
Record set England & Wales Births 1837-2006
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In 1881 he and his brother Charles Albert were with their step grandfather at Upton Street, Gloucester Barton St Michael, Gloucester, Gloucestershire:

First name(s) Last name Relationship Marital status  Sex  Age  Birth year  Occupation  Birth place
William Bulmer Head Married Male 48 1833  Vicar St James Gloucester  South Shields, Durham
Julia Isabella Pearett Step Daughter Single  Female  44  1837  -  South Shields, Durham
Alice Margaret Jervis Step Daughter Married  Female  34  1847  -  Folkestone, Kent
Robert Glover Cook Flower Step Grand Son Single  Male  20  1861  Student  Norfolk
Charles Albert Flower Step Grand Son Single  Male  17  1864  Student  Marylebone, Middlesex
Henry Stone Visitor Single Male 80  1801  Mariner  Folkestone, Kent
Sarah Farley Servant Single Female  49  1832  Ladys Maid  Folkestone, Kent
Anne Bloodworth Servant Single Female  23  1858  Cook (Dom)  Dursley, Gloucestershire
Clarissa Eliza Clessold Servant Single Female  27  1854  Parlour Maid  Stroud, Gloucestershire
Anne Jane Clessold Servant Single Female  18  1863  Housemaid  Stroud, Gloucestershire

Ref: RG11
Piece number 2536
Folio 100
Page 16

Combined: RG11, piece 2536, folio 100, p. 16
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Mark Flower, a descendant of his brother Charles Albert, reports that Robert G C Flower married He married Ellien Fetherstonehaugh.  As yet no record of this can be found in Ireland.
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But the 1901 census does not corroborate that forename for his wife:

Residents of a house 95 in Irish Street (Enniscorthy Urban, Wexford)

Surname Forename Age Sex Relation to head Religion Birthplace  Occupation  Literacy  Irish Language  Marital Status
Flower Robert G C 40 Male Head of Family Church of Ireland  England  Dist Insp. R.I.C  Read and write  - Married
Flower Rose   33 Female Wife Church of Ireland Westmeath Co  -  Read and write  -  Married
Flower Eilleen 12 Female Daughter Church of Ireland  Co Longford  Scholar  Read and write  -  Not Married
Brown Ellen 62 Female Servant Church of Ireland  Co Antrim  Nurse-Domestic Servant  Read and write  - Not Married
Donaghy Lizzie 25 Female Servant Roman Catholic  Co Tyrone  Cook Domestic Servant  Read and write  - Not Married
Keenan Maria 25 Female Servant Roman Catholic  Co Donegal  Parlour Maid Domestic Servant  Read and write - Not Married
Fee Peter 28 Male Servant Roman Catholic Co Tyrone  Groom Domestic Servant  Read and write  -  Not Married
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I wonder if this marriage might have been his:

Party 1 Name ROBERT FLOWER
Party 2 Name ROSA BRISCOE
Date of Event 11 August 1885
Group Registration ID 2337100
SR District/Reg Area Rathdown
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Their marriage index:

Party 1 Name ROBERT FLOWER
Party 2 Name ROSA BRISCOE
Date of Event 11 August 1885
Group Registration ID 2337100
SR District/Reg Area Rathdown
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