Continuity mistake: When William takes Anna back to his flat, after the orange juice incident. His shirt is stained, she comes into the flat and changes. Then she leaves. When she returns to get her books, his shirt is still stained but after she kisses him the stain is gone. An impressive kiss...
Continuity mistake: Every time they show the outside of the bookstore, on the left you see the same adult drying a child's tears.
Continuity mistake: Despite the passage of time, every time we see the back of the door in the book shop the same post is visible in the basket.
Revealing mistake: In the scene where they are all having a farewell dinner at Tony's restaurant. At the end of the meal they are all scattered around the restaurant, the camera is on Bella and Honey and in the background, outside the restaurant, 4 extras walk past, 3 at the front and one behind. The next shot is at the window where Max and William are sat, again the 4 extras walk past in exactly the same order and positions. They are the same people because one of them has a pink top on and you see that twice.
Continuity mistake: In one scene in the bookstore, there are three copies of a guide to Germany on the table next to Hugh Grant. In one clip, there are three spines, in the next two of the books have been turned round.
Continuity mistake: When William is interviewing Anna in the hotel suite, behind the lever door handles, there are two wide, brass, open lattice finger plates, which change to narrow, brass, closed lattice finger plates.
Plot hole: At one point, driving down Haymarket, they turn left into a side street to take a shortcut round Trafalgar Square. The next scene shows the Rhys Ifans character stopping the traffic next to Admiralty Arch to let the car come out of a side street. However, to get to the street out of which they are shown as emerging, the car would have had to drive all the way round Trafalgar Square and turn left off Cockspur Street, almost back where they started. The street they turned into off Haymarket comes out on Pall Mall East and the only way to go is along the north side of Trafalgar Square. So unless there's a wormhole between the two streets, the shortcut was anything but.
Continuity mistake: In the scene where they are all having a farewell dinner at Tony's restaurant, first the spaghetti is in the large bowl with Tony mixing, then suddenly the spaghetti has been dished to to each person's individual bowls.
Continuity mistake: In the scene where William visits Anna on the set of her period film and they have a discussion near the trailers, the same man pushing a trolley is in not one but three cuts back to Anna.
Continuity mistake: In the scene just after Anna opens the door and all the photographers are outside, Spike walks to the front door in his grey underwear. Just before he opens the door the underwear is covering only one butt cheek (his left). The next shot outside the house the underwear is adjusted and covers both butt cheeks but then when he enters the house and is checking himself out in the mirror, his butt cheek is exposed again.