When Amanda is searching for her holiday, on the net appears a window with the countries' flags. The old South African flag is used instead of the current, Peru's flag is used as Poland's and Union Jack is used as England's flag.
When Amanda first meets Graham, at approximately 1:10 AM, she says that she arrived around six hours earlier. That would be 7:00 PM. It would have been completely dark outside at that time of year in that location. Yet Amanda was seen arriving at the cottage while it is still daylight.
Iris briefly considers ending it all by breathing in gas fumes from her cooker but the UK changed to Natural Gas decades ago. The previous Coal Gas would put you to sleep with a couple of breaths and kill you in minutes. Natural Gas is not toxic at all and could only kill you by displacing all the air in a room, which since it is lighter than air is unlikely.
In the scene where Iris is looking through Amanda's DVD collection (approximately 34 minutes into the movie) there are two identical copies of The Glass House visible on the same shelf just a few DVDs apart.
When Graham and Amanda are in the car after their date, Amanda says that she is leaving in nine days and doesn't want to make things complicated. But later that night, at Graham's house, she says that she is leaving in one week.
Iris steps off to the side and you clearly see her walk over to the other side of the aisle. (When Iris walks Arthur down the aisle at the ceremony, she steps off to the right. In the next shot, she is on the other side of the aisle.)
When Amanda is drinking her hot chocolate with marshmallows with Graham and the girls, she gets her milk mustache. The milk is small mustache in the middle. In the very next shot, when she hasn't drunk any more, the mustache is large and covers the length of her top lip. Then in the next shot it is small again.
When Amanda pulls up to the shop in her car after her wild ride, the wide shot from outside the car shows her putting her right hand up to her forehead, leaving the left down. When they cut to a close shot of her from the front, the hands are reversed, and she brings her left hand down from her forehead and the right is near her side.
When Graham and Amanda are laying in the tent with the girls, one of the girls says something about never having grown up visitors that are girls. It's likely that their Aunt Iris would visit on a regular basis.
When talking with Graham at his home, after his daughters have gone to bed, Amanda's earrings change length (position) throughout the conversation with him. The earrings are a gold chain that slides through the ear lobe.
When Iris first views Amanda's bedroom there is no acrylic bench at the foot of the bed.When she is in bed and discovers the motorized blinds and the camera pans away from the bed, there it is at the foot of the bed.
Near the start of the movie when Ethan heads upstairs to talk to Amanda, she throws a trainer/sneaker at him. It disappears from where it lands in the next few shots, then reappears when Amanda throws the second one. Then when we next see Ethan and the camera tracks across the room, both trainers/sneakers have disappeared.
The middle knob on the stove is positioned side to side when Iris is in the kitchen, but after she lights the match, you see a close up of the knobs when she turns the right one. In that shot the middle knob is positioned straight up and down. When the computer "dings" and you see the front of the stove as she turns off the gas, the middle knob is again positioned side to side.
When Iris is running around the house the way her scarf is tied changes from the movie room to the exercise room and back when she is seen running up the stairs. According to the commentary the scenes were shot separately.
As Arthur and Iris talk in his office, his Oscar (behind him) faces left, then faces them, then faces left again. When it faces left, it is normal-size, but when it faces them, it is smaller-than-normal in relation to its base, but when it faces left again, is normal-size again.
More than halfway in the movie, after Amanda and Graham's meal at the restaurant. When Amanda gets out of the 4x4, the seat belt shoulder strap adjustment goes down, then back up on the post between the doors.
In the morning after Amanda and Graham have spent their first night together, at 49 to 50 minutes, Graham puts on his sport coat. At first, his left side shirt collar is above his coat collar. A moment later his shirt collar is under his coat collar and then reappears above his coat collar.
When Iris arrives in L.A. and is taking a taxi to Amanda's house, the cab drives along with the ocean to its right and turns left onto Sunset Blvd - this means that it is driving south. To get to Sunset Blvd from LAX airport, however, one would need to drive north.
When the camera pans away and shows the limo taking Amanda through town on her way to find Iris's cottage, the cars are driving (and parked in town) on the right side, not the left side as it shows later when Amanda drives to town and almost hits someone because she gets on the wrong side.
(at around 32 mins) While Amanda is lying in bed in England she sees an advert for the movie "Deception" out on Christmas Day. Movies don't show on December 25 in the UK; it would come out on 26th December and would say "Boxing Day".
When Amanda is lying in bed in England and sees her advert on the television, it is clear she is watching Little Britain before it comes on. 'Little Britain' is broadcast on the BBC in England, which gets its money from TV licensing and does not show adverts. (Although it may however have been shown on the cable channels Dave or G.O.L.D. which are both commercial networks which do have adverts.)
When Iris is on the plane to L.A, she is replying to a message from Jasper on her blackberry. When she has sent it, there is a quick shot at the 'message sent' and the date is clearly shown as Weds 18th Dec. However, the film is set for Xmas 2006 and December the 18th 2006 isn't a Wednesday, neither is December 2005.
Iris's house is constructed of a flat, smooth slate-like stone. However, in England, the main building material for houses such as Iris's would have been flint, a fist-sized gray rock, that would have given the house a rough pebbly look.
When Iris is driving Arthur back to his house, he asks where she is from. She says Surrey, to which Arthur says Cary Grant was from Surrey as well, to which Iris agrees. Cary Grant was originally born in Bristol, which is not in Surrey.
When Amanda and Graham are together, Amanda picks up his phone and reads the caller ID "Sophie" and later in the movie "Olivia". In this day and age, many young children have cell phones. With the children's mother having died, it is likely that Graham would allow each to have a cell phone in order to reach him when they needed to.
When Amanda is looking through a list of countries to visit on the internet, the icon next to South Africa is a picture of the old South African flag, which was replaced in 1994! However, it may just be that she is looking at a website that's not up-to-date!
When Amanda is first taken to the cottage she has to walk as the limo can't get up the path, later when she wants to go back to the cottage she has to walk as the limo can't make it up the path, however when she is going home after the holiday the (exact same) limo is waiting outside the gate for her at the top of the lane it apparently can't get up.
When the limo is returning Amanda to the the cottage before New Year, the shot towards the driver shows the scenery moving by, yet both the tachometer and the speedometer readings are zero. The car is either not running, or the gauges do not work.