In the same scene, Jessica is wearing a camel color sweater with a crimson scarf. Cut to the other guests in the same manor, cut back to Jessica, she is now wearing a V-neck olive green sweater (with a gold chain clashing with her sweater's neckline).
After the accident Tom says the ball joints couldn't be worn. Worn ball joints would not cause a car to veer uncontrollably.
Uniformed Gardai (Irish cops) do not carry guns in holsters on their waists.