Short answers, pulled from the story.
Harding, Howell and Company's Grand Fashionable Magazine was an 18th-century shop at 89 Pall Mall in St James's, London, open from 1796 to 1820. It is considered a forerunner of the modern department store. The shop was divided into four departments selling fur and fans, dress fabrics, haberdashery, jewellery and clocks, and perfume and millinery.
Harding, Howell and Co. was located at 89 Pall Mall in St James's, London.
Harding, Howell and Company opened in 1796 and closed in 1820, operating for approximately twenty-four years.
Harding, Howell and Co. sold fur and fans, fabric for dresses, haberdashery, jewellery and clocks, and perfume and millinery, spread across four separate departments under one roof.
Harding, Howell and Co. is considered a forerunner of the modern department store because it divided its retail space into four distinct themed departments selling a wide variety of goods under one roof, anticipating the organizing principle that later department stores would adopt on a larger scale.