The sound of the judge banging a gavel is heard several times in the courtroom scenes. In England only auctioneers use gavels; judges have never done so.
Edith buys an orange 2d stamp which she attaches to a letter she then posts. Earlier in the film there are close-up shots of letters with single 1d red stamps attached. The one-penny rate for letters ended in 1918.
CPS (Child Protective Services) not only did not exist in 1920s England, but it is an organisation that only exists in the modern USA. According to a newspaper article of the time, Rose was instead reported to the Inspector for Cruelty to Children.
There are references to Rose's daughter been taken off her by the CPS; a modern organisation that begun in the 1980s.
After Edith collapses at the trial the judge says "We'll convene there" when he means "We'll adjourn there".
The UKs first female Asian police officer did not serve until the 1970s.
There is reference to the WPC booking a motorcyclist for not wearing a helmet. This was not an offence in the 1920s with compulsory helmets not brought in until the early 1970s. However this was explained by local by laws in the film.
The Judge presiding over the case is black. The first black Judge in England and Wales was not appointed until 2004.