Factual error: Matilda searches for a library in what looks like the yellow pages. 'Library' is first under the 'L' section. Library starts with 'li'. Surely there would be something beginning with 'la', which would be before 'li'.
Factual error: It is stated that Miss Trunchbull competed in the Olympics in shot put, javelin, and hammer throw. According to her jersey those were the 1972 Olympics. The hammer throw wasn't added as an Olympic event for women until 2000.