Robert and Carson joke about the former chauffeur Taylor leaving to open a tea shop. Robert says he can't imagine that being successful. Taylor's of Harrogate near where Downton is situated is one of the biggest tea companies in the world.
The inclusion of erisypelas in the story line is of note because George Herbert, the 5th Earl of Carnarvon, who was the financial backer for Howard Carter, died in 1923 from shaving a mosquito bite infected with the bacteria which caused erisypelas, leading to blood sepsis and pneumonia. Downton Abbey is filmed at Highclere, which is the ancestral home of the Earls of Carnarvon. His death followed the discovery and opening of Tutahnkamun's Tomb and directly contributed to the legend of the Mummy's Curse.
Erysipelas is a bacterial infection of the upper skin characterized by sharply defined red patches. In previous times it was known as "holy fire" or "St. Anthony's Fire." Although today it is not fatal, among the more famous historical personages who died from it are Queen Christina of Sweden, John Stuart Mill, and Hall of Fame baseball manager Miller Huggins.
When Mary refers to conflict of the entail and the estate she calls it "The Great Matter", which is what Henry VIII's petition of divorce to Kathryn of Aragon was also called.
The discussion between Mrs. Crawley and the Dowager's Rose always winning the prize is reminiscent of the 1942 film Mrs. Miniver where the Lady Beldon always wins the contest in the town Flower Show.