Rats were actually a common sight in all of the royal residences, and Victoria had no fear of them.
During the costume ball, Strauss's "Wiener Bonboms" waltz is played as the guests dance. This piece was not composed until 1866.
Sir Robert Peel (Nigel Lindsay) is depicted as having a working-class Lancashire accent. While born in Lancashire, Peel was the son of wealthy industrialist Sir Robert Peel, 1st Baronet. He was educated at Harrow and Oxford and would have spoken with an upper-class accent.