Gillian tells Shirley that their house is vegan but is giving the dog muesli and milk. Vegans don't have any dairy products. Whilst it is possible that Gillian is using soya milk, that has never been supplied in glass "pinta" bottles like the ones in which cow's milk is delivered by the milkman.
When Shirley is with her son in the squat in Kirby he sees a couple of kids robbing a car. When the car drives away you can see that the kid driving is replaced by an adult stunt driver.
When Renos, the waiter says goodbye to Shirley, he says "kalo taxadhi" instead of "kalo taxidhi" for "good journey", thus revealing that the actor is not Greek.
In the US version of the film, when Gillian encounters Shirley choosing underwear for her holiday the phrase "garter belt" is dubbed over the words "suspender belt".
Shirley's school is in Liverpool, yet all the other girls in the school start singing Jerusalem with southern accents.
Despite being set in and around Liverpool, the railway station, where Jane takes Shirley to have her passport photos taken, is quite clearly St Pancras, in central London.