Her proable birth index:

First name(s)         Susan P
Last name             Lawrenson
Birth quarter         4
Birth year            1945
Mother's maiden name  Waddams
District              Redruth
County                Cornwall
Country               England
Volume                5C
Page                  194
Record set            England & Wales Births 1837-2006
_____________________


_____________________

Two of her children have her surname misspelled on their birth index sheets, Laurenson being used instead of Lawrenson.  So I have checked to see what her father used and the marriage of her parents, the index clearly has Lawrenson:

First name(s)       Cyril A
Last name           Lawrenson
Marriage quarter    2
Marriage year       1933
MarriageFinder      Cyril A Lawrenson married one of these people
                    Minnie K Waddams
Spouse's last name  Waddams
District            Brentford
County              Middlesex
Country             England
Volume              3A
Page number         373
Record set          England & Wales Marriages 1837-2005

From the 1939 Register and the subsequent additions to it, it looks as if Minnie in 1948 married a Weaser, Lawrence W Weaser to be precise.  It sounds like she and Cyril divorced as Cyril did not die until 1968.
_______________________

Their marriage index:

First name(s)       Jeremy W L
Last name           Tinley
Marriage quarter    3
Marriage year       1967
MarriageFinder      Jeremy W L Tinley married one of these people
                    Susan P Lawrenson
Spouse's last name  Lawrenson
District            Taunton
County              Somerset
Country             England
Volume              7C
Page number         1290
Record set          England & Wales Marriages 1837-2005
____________________