When Joanne graduates from university, the University Officers and the new graduates are all shown wearing American-style academic dress with a closed gown and a gold stole. English university graduates wear open fronted gowns with an academic hood and no stole. In addition, the new graduates are wearing royal blue gowns. Exeter University gowns are black; the hood is dove grey, edged in blue taffeta.
When speaking to her teaching after the lesson, Joanne addresses the teacher as "Professor." Male teachers in the UK are addressed either by name or as "Sir." Professors are addressed as "Professor" and professors don't teach in schools.
When she is turned down by Oxford, Joanne's father suggests she go instead to Exeter which is "a good school." Exeter is a university and universities in England are not called "schools" (although some of them call their separate faculties schools, such as the "School of Medicine".)
When Joanne's mother is first in hospital, she and her sister discuss their mother having "shots". In the UK they are called injections.
Prior to the scene set in 1990 when Rowling first imagines Harry Potter, an establishing shot is seen of the exterior of the train she is travelling on. The train has Virgin Trains livery - this company did not exist until 1997.
In the film, when J. K. Rowing looks at the first edition printing of Harry Potter and the Philosopher's Stone, the back cover shows an illustration of Dumbledore with a long, white beard. In reality, the back over of the first edition showed an unspecific wizard (possibly Dumbledore) with a short, brown beard. The illustration of Dumbledore seen in the film wasn't added until later editions of the book.
In a scene set in the early 1990s, Rowling is seen using the X-shaped road crossing at Oxford Circus in London. This crossing was installed in 2009.
The telephone number in the newspaper advert for English teachers in Portugal uses the 020 7xxx xxxx format which was not introduced until 1999, nine years after the scene is set. In 1990, all London numbers used the 01 area code.
Rowling's parents lament that due to their lack of means, they will have to send their children to "public school" to be educated. In England, a "public school" is a type of privately-run school funded by (prohibitively high) fees - the term "state school" should presumably have been used.
When Joanne is taking Jessica for walk in Edinburgh they pass by a bookshop called "Munro's Books" where a lady is fixing books in the front window. Later on, Harry Potter's book will be displayed in that same bookshop. However there's no such a bookshop in Edinburgh, as Munro's Books is located in Canada.
According to the own JK Rowling, she first saw her book in a bookshop in Princes Street in Edinburgh (most likely the British chain Waterstone's).
Rowling is advised to get an 'attorney' The correct term in the UK is lawyer.