Who is Mrs. Wharmby?

Mrs. Wharmby is the landlady of the New Inn. According to the story, Mrs. Wharmby was a friend to Paul's paternal grandmother.
In chapter 4, Paul goes to collect Mr. Morel's pay one Friday afternoon. The whole process, however, is too much for Paul's sensitive nature. Around him are the families of colliers, who have come to collect the wages of their loved ones. The assembly is a noisy one, and sometimes, an atmosphere of general confusion prevails. The men dispensing the wages are Mr. Braithwaite and his clerk, Mr. Winterbottom.
When Paul's name is called, he can barely answer; he is too nervous to speak up. Fortunately, Mr. Winterbottom notices Paul and alerts Mr. Braithwaite to the boy's presence. After collecting Mr. Morel's wages from Mr. Braithwaite, Paul must hand back some of the money for rent and tools to Mr. Winterbottom. Even here, Paul suffers great indignities; he can barely count properly, and it's clear that he's struggling to communicate with Mr. Winterbottom.
Finally, Paul's ordeal ends, and he is relieved. He makes his way to the New Inn to wait for his father. Here, we are introduced to Mrs. Wharmby, who is the landlady of the inn. When Paul reaches the inn, Mrs. Wharmby curtly tells him that his father has not yet shown up. Her manner towards Paul is cold and somewhat scornful. It's clear that Mrs. Wharmby doesn't think very much of Paul.