When William Rackham receives a final demand bill from the coal merchant, the total does not match the sum of the items: October £6 15s, November £8 10s, penalty payment 10s, which should add up to £15 15s. However the total shown on the bill is only £15.
The action takes place in the 1870s. However an instrumental version of "The Sunshine of Your Smile" (written in 1913) is heard during the scene in the brothel when William Rackham first meets Sugar.