The Lebanese jeweller Nada Ghazal can’t hear the doorbell ringing at her London townhouse despite it being loud and clear. When she realises, and after opening the door to her visitor, she excuses herself for a moment then returns with a fresh battery in her hearing aid – one you’d never know existed under her enviably chic chin-length black bob. Physically, she is a mix of Audrey Hepburn and Béatrice Dalle’s Betty Blue, with a soft, lightly accented voice and a demureness that makes other women