Her baptism from an image of the Register page, thanks Ancestry, transcript by me:

“                     [ Page 45 ]
“BAPTISMS solemnized in ST MARY’S CHURCH in the Parish
“  of St MaryLeBone, in the County of Middlesex, in the Year
“  One thousand Eight hundred and Fifty Eight
“. . . .
“When Baptized:       1858 Aug 27
“No:                  365
“Child’s Forename:    Evelyn Emma
“Parents’ Forenames:  Robert & Matilda Caroline
“Parents’ Surname:    Stopford
“Abode:               50 Montagu Square
“Profession:          Gentleman
“Celebrant:           Robt Dullard(?)
“When born:           16th July 1858
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In 1889 there is a marriage between her and Walter Copland Perry or William Mumford.  The 1891 census should resolve which was her husband.

In 1891, she, aged 31, was married to Walter Perry aged 75 and with a freshly born son, possibly 5 weeks old; they were living at Manchester Square, St Marylebone, Marylebone, London:

First name(s)  Last name  Relationship  Marital status  Sex  Age  Birth year  Occupation  Birth place
Walter Copeland         Perry       Head  M  M  75  1816  Living on his means  Norfolk
Evelyn Emma             Perry       Wife  M  F  31  1860  -                    London, Middlesex
Evelyn Walter Copeland  Perry       Son   -  M  5w  1886  -                    London, Middlesex
Ellen                   Rodgers     Serv  S  F  31  1860  Cook                 London, Middlesex
Louisa                  Lower       Serv  S  F  27  1864  Housemaid            London
Benjamin                Holley      Serv  S  M  20  1871  Man servant          Islington, Middlesex
Ellen                   Wilkinson   Serv  S  F  15  1876  Kitchen maid         Mammersmith, Middlesex
Margarete               Williamson  Serv  S  F  19  1872  Ladies maid          London
Annie                   Sandars     Serv  S  F  28  1863  Nurse                Peckham, Surrey

Ref:
Archive reference  RG12
Piece number       94
Folio              184
Page               2
Combined           1891 ref: RG12, piece 94, folio 184, p. 2
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And in 1911 it was considerably clearer that young Evelyn really was her son,

First name(s)  Last name  Relationship  Marital status  Sex  Age  Birth year  Occupation  Birth place
Walter Copland         Perry      Head M  M  96  1815  -                      Borfolk Wichingham
Evelyn Emma            Perry      Wife M  F  52  1859  -                      London Paddington
Evelyn Walter Copland  Perry      Son S  M  20  1891  Aeronautical engineer  London Marylebone
Harry                  Roe        Serv  W  M  39  1872  Butler                 Bedfordshire Dunstable
Sarah                  Wood       Serv  S  F  55  1856  Cook housekeeper       Lincolnshire Swinshead
Catherine              Taepey     Serv  S  F  43  1868  Ladies maid            La Loseth Castle Bellingham
Henry                  Wecks      Serv  S  M  16  1895  Young footman          Hampshire Red Rice
Doris                  Harvey     Serv  S  F  18  1893  Under housemaid        Epey Burnham on Crouch
Isabel Daisy Dora      Cook       Serv  S  F  20  1891  Kitchenmaid            Dyon Wattington
Louisa                 Goodchild  Serv  S  F  29  1882  Housemaid              Herts Ashwell
Christina              Armour     Serv  S  F  53  1858  Nurse attendant        Lanackshire East Kilbride

1911 ref: RG14 PN555 RG78 PN19 RD7 SD2 ED19 SN121
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And by 1939 she just had to be widowed, her birth date was the same as when she was baptised and she had downsized to "plumtrees" Cross Road, Broomhall, Bagshot R.D., Surrey:

First name(s)  Last name(s)  Birth date  Sex  Occupation  Marital status  Schedule  Schedule sub number
Evelyn E  Perry    16 Jul 1858  F  Private Means    W  177  1
James R   Wilford  05 Dec 1869  M  Butler           M  177  2
Mary A    Biddic?  11 Jun 1874  F  Domestic Worker  W  177  3
Eva A     Midlane  04 Feb 1878  F  Maid Attendant   S  177  4

1939 ref: RG101/1935B/023/20
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Her death index:

Name:                          Age at Death (in years):  
PERRY, EVELYN EMMA COPLAND     90  
GRO Reference: 1948  D Quarter in HARROW  Volume 05F  Page 430
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Her probate index:

1949
PERRY, Evelyn Emma of 29 Thurloe Square Kensington London widow died 25 December 1948 at Chiswick House Pinner Middlesex  Probate London 25 April to The Public Trustee.
Effects £37062 18s. 6d.

Will ordered.
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