Her baptism from the Bishop’s Transcript:

“1802 Barton Seagrave
“An account of the Baptisms deaths & marriages in the Parish of Barton Seagraves from April 1902 to April 1903
“. . .
“Eleanor Elizabeth Stopford baptized October 3d. 1802.”
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She married in 1832, a tad late.
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In the 1841 census it looks like they were in a hotel at Jermyn Street, St James, St James Westminster, London:

(Omitting all the other occupants)

First name(s)  Last name  Sex  Age  Birth year  Birth place
Ambrose  Isted  Male    40  1801  -
Eleanor  Isted  Female  25  1816  -

Ref:
Archive reference  HO107
Piece number       736
Book number        2
Folio number       26
Page number        46
Combined:          1941 ref: HO107, piece 736, book 2, folio 26, p. 46
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In 1851 they had a household of 16 live-in servants for the two of them at Main Street, Ecton, Wellingborough, Northamptonshire:

First name(s)  Last name  Relationship  Marital status  Sex  Age  Birth year  Occupation  Birth place
Ambrose    Isted      Head  M  M  54  1797  Landed proprietor         Northamptonshire
Eleanor E  Isted      Wife  M  F  48  1803  Landed proprietor's wife  Barton Seagrave, Northamptonshire
Anna       Winfield   Serv  U  F  42  1809  House keeper              Walton, Surrey
Elizabeth  Brown      Serv  U  F  27  1824  Lady's maid               Stockwell, Surrey
Sarah      Wright     Serv  U  F  25  1826  Cook                      Barton Seagrave, Northamptonshire
Jane       Cockrill   Serv  U  F  28  1823  Laundry maid              Cosgrove, Northamptonshire
Sarah      Judd       Serv  U  F  29  1822  House maid                Thorpe Malsor, Northamptonshire
Ann        Butlin     Serv  U  F  23  1828  House maid                Northamptonshire
Mary       Tarry      Serv  U  F  19  1832  Dairy maid                Ecton, Northamptonshire
Rowena     Bethay     Serv  U  F  19  1832  Kitchen maid              Barton Seagrave, Northamptonshire
Sophia     Baizley    Serv  U  F  52  1799  Laundry maid              Ecton, Northamptonshire
William Cockayne   Serv  U  M  41  1810  Butler                    Northamptonshire
George     Barber     Serv  U  M  27  1824  Gardener                  Burnham, Buckinghamshire
William    Spong      Serv  U  M  23  1828  Footman                   Kent
Thomas     Armstrong  Serv  U  M  29  1822  Coachman                  Walton, Hertfordshire
Thomas     Pridmore   Serv  M  M  45  1806  Groom                     Northamptonshire
George     Pridmore   Serv  U  M  16  1835  Page                      Dingley, Northamptonshire
William    Pridmore   Serv  U  M  13  1838  Scholar                   Dingley, Northamptonshire

Ref:
Archive reference  HO107
Piece number       1743
Folio              32
Page               1
Combined:          1851 ref: HO107, piece 1743, folio 32, p. 1
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I put in a search for all of the 1841, 1851 and 1861 censuses to find any possible child, that is a person with a surname of isted and born in 1842 plus or minus 10 years.  this resulted in 362 people.

reducing the are to Northants gave zero people.

It would take a very long time to pursue all this.  But it’s a thought.

Currently I only have the Burke’s statement that she dsp.

But no baptisms can be found from 1831 to 1851 with the surname of Isted and the parents’ names of Ambroase and Eleanor.  So that confirms Burke quite a bit.
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Her death index:

Name:                          Age at Death (in years):  
ISTED, ELEANOR ELIZABETH       49  
GRO Reference: 1851  D Quarter in BRIGHTHELMSTON  Volume 07  Page 210
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Her burial abstract:

First name(s)                       Eleanor Elizabeth
Last name                           Isted
Birth year                          1802
Age                                 49
Death year                          1851
Burial year                         1851
Burial date                         18 Oct 1851
Parish                              St Mary Magdalene
Place                               Ecton
Denomination                        Anglican
Residence                           Ecton NTH
County                              Northamptonshire
Country                             England
Repository                          Northamptonshire Archives
Event type                          Burial
Burial unique reference identifier  B0286
Archive reference                   114P/212
Record set                          Northamptonshire Burials
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No probate found.

Their marriage abstract:

First name(s)            Eleanor Elizabeth
Last name                Stopford
Marriage year            1832
Marriage day             26
Marriage month           Jul
Marriage place           Barton Seagrave
Parish                   Ecton
Marital status           B
Spouse's first name(s)   Ambrose
Spouse's last name       Isted
Spouse's title           -
Spouse's parish          Barton Seagrave
Spouse's marital status  S
Event Type               Marriage
By Banns or licence      License
County                   Northamptonshire
Country                  England
Record set               Northamptonshire Marriages
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