In the opening scene Sir Robert and his assistant Wainright are working on a paralyzed girl's legs. The story is set in 1880 yet the young girl clearly shows evidence of a recently-removed band-aid from the side of her right ankle. Adhesive bandages were invented in 1920.
In 1880, the Baroness talks of a "fascinating writer" Sir Arthur Conan Doyle. Doyle did not publish his first minor work until 1883, and was not well-known until the publication of the first Sherlock Holmes story - "A Study in Scarlet" in 1887.
The winning lottery number only has 4 digits (and the ticket only has space for 4 digits) implying that there could only ever be 10,000 different lottery numbers in that lottery. However, Sardonicus wins enough money to become a baron and buy a castle. The only way this could happen is if either each lottery ticket cost a great deal of money, or if the organizers of the lottery made a huge loss.