She married in 1960, so she is highly unlikely to have been less than 18 then, so was born in 1942 or before.  A search of the twenty years from 1922 to 1942 produces three Susan J Coles births:

Last name  First name(s)  Year Of Birth  Location
Coles      Susan J        1938           Knaresborough, Yorkshire
Coles      Susan J        1940           Hendon, Middlesex
Coles      Susan J        1942           Surrey Mid Eastern, Surrey

I have yet to find any information to confirm any of these.  She could have been born abroad.
_______________________

After the death of her husband this looks possible as her second marriage:

First name(s)       Susan J S
Last name           Sackville
Marriage quarter    2
Marriage year       1982
Marriage Finder     Susan J S Sackville married one of these people
                    John R Rathbone
Spouse's last name  Rathbone
District            Kensington & Chelsea
County              London
Country             England
Volume              13
Page number         1448
Record set          England & Wales Marriages 1837-2005
_______________________

No death found up to 2021.
_______________________

Their marriage index:

First name(s)       Lionel G S
Last name           Sackville
Marriage quarter    2
Marriage year       1960
Marriage Finder     Lionel G S Sackville married one of these people
                    Susan J Coles
Spouse's last name  Coles
District            Westminster
County              London
Country             England
Volume              5C
Page number         553
Record set          England & Wales Marriages 1837-2005
_________________