(at around 25 mins) At the beach, the relative positions of the two characters change from head-to-head to head-to-toe as they lie on the sand.
During the opening credits, when she is riding her bike home from the pool, she goes around a corner and a motorcycle comes up behind her and passes her on the left. The scene immediately cuts, and the motorcycle is on her right. Schlepperman.
Emma and the other students are seen wearing mortarboards as they graduate in Edinburgh, however these are not worn at graduation at the University of Edinburgh (nor generally other universities in Scotland).
When they are returning from their graduation party the time is shown as 6am but it's hardly light. In Edinburgh in July it would be fully light.
The dress code for graduation at Edinburgh is a dark suit or highland dress with white tie for men, dark suit or dress for women. When they are on their way back to Emma's flat they all have random clothes on under their gowns.
The Coronas hit, "The Rhythm of the Night", was first released in December in 1993. In the movie it appears in July 1993, 6 months prior to its first actual release.
On July 15, 1994, Dexter tells his mother that he won't be able to stay to visit her that evening because he already has plans to attend the premiere of Jurassic Park (1993). The UK premiere of Jurassic Park took place a year to the day earlier, on July 15, 1993.
On 15 July 2000, Dexter and Emma meet again at Colin's wedding in London. Dexter takes Emma outside onto the roof, overlooking St Paul's cathedral. In the background you can see two skyscrapers. One of these is the Heron Tower, which wasn't completed until late 2010, having not even been granted planning approval until mid-2002.
On 15 July 1995, Dexter uses a Nokia 6110. This model was released in 1997. Bottom connectors are clearly visible at 44:15. Previous models had different connectors and different antenna.
At 1:18:45, where they were supposed to be in 2003, we see a BMW X6 parked on the side of the road, which in 2007 was a concept model of the BMW company and was later released in 2009.