Per company records, Mrs Bettina Claire Lascelles HARDEN (née TAYLEUR), MBE, was born on 16 August 1949. The birth of a Bettina C TAYLEUR was registered in Battersea in Q3 1949, and her mother's maiden name was given as Pierce-Goulding. I cannot find a marriage record for her parents on Free BMD, but it seems that her mother was Enid Monica TAYLEUR, née PIERCE-GOULDING (3 IV 1915 - 8 XII 1988).
It appears that Mrs Harden's father's (second?) marriage to Patricia F T HANNINGTON was as that lady's third husband. She was born as Patricia Frances Thomasine HEWITT (12 VIII 1916 - 23 I 1994), and was a great-great-granddaughter of the 2nd Viscount Lifford.