Who is Lady Steeple from Venetia and what is their importance?

Lady Aurelia Steeple is Venetia's mother. She abandoned her family and left Venetia in her father's care years before, although Venetia was led to believe she was dead. When Venetia meets her mother, she persuades her to do one act of kindness and write her an invitation to come visit for as long as she wants. Aurelia has no love for her daughter and the invitation is forced not genuine.