The only clear record of his birth is on the 1911 census.  No birth or baptism record found.

No record found for his death.  Was it abroad?  But see below!

He was alive in 1929 when his mother died and he was sworn in as executor.
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He was alive in 1939 at 9 Vicarage Gate, Kensington, Kensington And Chelsea, Kensington, London and giving his birth date:

First name(s)        Sackville E           [sic]
Last name(s)         Stopford
Birth date           30 Apr 1887
Birth day            30
Birth month          4
Birth year           1887
Sex                  Male
Marital status       Single
Occupation           Jnr Technical Examiner Land War
Address              9 Vicarage Gate, Kensington, Kensington And Chelsea
Place                Kensington
Borough / district   Kensington
County               London
Country              England
E. D. letter code    AMBA
Schedule             310
Schedule sub number  1
Archive reference    RG101/0306G/015/7
Piece number         0306G
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In 1942 this marriage was found:

Surname    First name(s)  Spouse      District  Vol  Page
Marriages Jun 1942   (>99%)
Mills      Violet M       Sackville   Coventry   6d  2226
Sackville  Edward S       Mills       Coventry   6d  2226

I suspect the marriage certificate needs ordering to see if he was involved in this.

But a Sackville child with a Mills mother was born in Dec 1945, over three years after his death, so I do thing this marriage was him.
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His death index:

Name:                         Age at Death (in years):  
SACKVILLE, EDWARD STOPFORD    57  
GRO Reference: 1943  D Quarter in KENSINGTON  Volume 01A  Page 231

No will found.

I suspect he remained single after 1939 and dsp.
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