Her baptism, with birth date:

First name(s)           Anne
Last name               Powys
Birth year              1745
Birth date              19 Sep 1745
Baptism year            1745
Baptism date            20 Oct 1745
Father's first name(s)  Thomas
Mother's first name(s)  Henrietta
Parish                  St James, Piccadilly
County                  Middlesex
Country                 England
Archive                 City of Westminster Archives Centre
Record set              Westminster Baptisms

The text from an image of the Register is:

[  St James, Piccadilly  aka  St James, Westminster ]

“Bapt               October 1745                      Born
.   .   .  
20  Anne Powys of Thomas Esqr and Henriettaa .  .  .  Sep 19
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Her burial trancript:

First name(s)         Ann
Last name             Doughty
Sex                   Female
Age                   70
Birth year            1747
Burial year           1817
Burial date           25 May 1817
Parish                Hanworth
Diocese               Norwich
Husband's first name  Robert Lee
County                Norfolk
Country               England
Archive               Norfolk Record Office
Archive reference     PD 226/6
Archive year range    1813-1975
Page                  3
Record set            Norfolk Burials

But no will can be found on PCC.
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Their marriage index:

First name(s)           Ann
Last name               Powys
Residence               St George Hanover Square
Marriage year           1776
Parish                  St George, Hanover Square
Spouse's first name(s)  Robert Lee
Spouse's last name      Doughty
Spouse residence        St George Hanover Square
County                  Middlesex
Country                 England
Archive                 City of Westminster Archives Centre
Record set              Westminster Marriages
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