Dame Nellie Melba (1861-1931), the first classical music performer to come from Australia, was the greatest operatic soprano of her day. She was born Helen Porter Mitchell but changed her name in honor of her home town Melbourne, Australia.
At around 3:45, while discussing Lady Raven, Mr Carson uses the phrase "north of the park" as a dismissive way of saying she is down on her luck. It was a snobbish idea based on the area of houses north of Hyde Park in London; society people generally lived to the south, in Belgravia.
The Rossetti whose poetry is quoted is British poet Christina Georgina Rossetti (1830-1894).
Dame Nellie Melba, New Zealander Kiri Te Kanawa, sings Puccini's O Mio Babbino Caro which was opening music of Room With a View, which also starred Dame Maggie Smith.
Actresses Penelope Wilton and Joanna David have both previously played the role of Mrs. Gardiner in film versions of Pride and Prejudice