Who is Polly Cockpurse from A Handful of Dust and what is their importance?

Polly Cockpurse is a friend of Brenda's who has married into money and is the social queen of the group. She always has entertainment and parties at her house, where everyone considered important is in attendance. Tony doesn't like her much, and when talking to his son compares her appearance to a monkey. From then on John Andrew refers to her as the monkey-woman.