On her death certificate she was 79, widow of Robert Dampier Hallifax, Brigadier and Colonel of HM 78th regt.  The informant was B A Summers, present at the death and also of Ellerslie, Chilston Road, Tunbridge Wells.

TFPL, Sep 2004: I am unable to find her in the 1881 census, nor any of her famly apart from Katherine Maria in Liverpool.  I wonder if they were abroad then?

At her burial, the celebrant was S George Bird, the entry no was 5805 and the grave no was 78 in Class B, section 7.
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In the 1861 census she was a widow aged 48, born in Dover, Kent and living in Portsea, Hants, with six of her children, including Robert who is not found elsewhere, and three servants:

Name Relation Condition Sex Age Birth Year Occupation  Disability  Where born

HALLIFAX, Harriet Head  Widow   F 49  1812  Widow Of...  Dover, Kent
HALLIFAX, Kate Daughter Unmarried   F 18  1843  Alverstoke, Hampshire
HALLIFAX, Pauling Daughter  Unmarried  F 16  1845  Plymouth, Devon
HALLIFAX, John Son Unmarried M 15 1846  Cadet R N  Ireland
HALLIFAX, Emily Daughter F 13 1848  Scholar  Ireland
HALLIFAX, Robert Son M 11 1850  Scholar  East Indies
HALLIFAX, Constance Daughter F 8 1853  Scholar  East Indies
PATTERSON, Mary A Servant Unmarried   F 30  1831  Lodge Maid ..., Durham
APPS, Jane Servant Unmarried F 22 1839  Cook Dometic Servant  York Romaldkirk
STAMP, Olive Servant Unmarried F 26 1835  House Maid  ..., Sussex
REEVES, Phoebe Servant Unmarried F 23 1838  Parlourmaid  ..., Dorset

Piece: 644 Folio: 98a Page: 36

Registration District: Portsea Island
Civil Parish: Portsea
Municipal Borough: Portsmouth
Address: 5, Sussex Place, Portsea, Portsmouth
County: Hampshire
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In 1871 she was head of house:

Name Relation Condition Sex Age Birth Year  Occupation  Where Born

HALLIFAX, Harriett Head F 59 1812   Kent
HALLIFAX, Georgiana Daughter F 31 1840  Ireland
HALLIFAX, Catharine Daughter F 28 1843  Hampshire
HALLIFAX, Pauline Daughter F 26 1845  Devon
HALLIFAX, Constance Daughter F 18 1853  India
SPEARRY,  Sarah     Servant F 21 1850  Dorset
BAUGH,    Harriet Servant F 22 1849  Wiltshire

RG number: RG10 Piece: 1145 Folio: 85 Page: 8    

Registration District: Portsea Island Sub District: Landport
EnumerationDistrict: 42  Ecclesiastical Parish:

Civil Parish: Portsea Municipal Borough: Portsmouth
Address: Brunswick Terrace, Portsea, Portsmouth
County: Hampshire
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In 1881 she was at the same place this time with four of her children but her name had been incorrectly spelled and then hopelessly mistranscribed (2016: I have sent in corrections to change the names to ‘Halifax’, but they cannot be corrected to the true ‘Hallifax’):

Name Relation  Condition Sex Age Birth Year  Occupation  Disability  Where Born

HALYAN, Harriet Head Widow F 69 1812  Fundholder  Dover, Kent
HALYAN, Georgiana Daughter Single F 41 1840  Ireland
HALYAN, Pauline Daughter Single F 36 1845  Plymouth, Devon
HALYAN, Robt Son Single M 31 1850  Captain In Army  British Subject  India
HALYAN, Constance Daughter Single F 28 1853  British Subject  India
FACEY, Florence Servant Single F 24 1857  Cook Domestic Serv  Tiverton, Devon
BIGNELL, Jane Servant Single F 27 1854  Parlourmaid Domestic Serv  Stonehouse, Hampshire
PRATT, Sarah Servant Single F 26 1855  Housemaid Domestic Serv  Chichester  Sussex

Piece: 1159 Folio: 118 Page: 6
Registration District: Portsea Island
  
Civil Parish: Portsea Municipal Borough:
Address: 4, Brunswick Ter, Portsea
County: Hampshire
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Jnu 2016, TFPL: Her baptism has now appeared on FindMypast together with the image of, probably, the Bishop’s Transcript, annotated as of St Mary’s Dover, reading:

“Christnings in February 1812
“19 Thompson  Harriet Daughter of Robert & Harriot.  [Poss. ‘born’:] Jan 20”
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