Factual error: On the drive to Norwich, Stimpson wants Laura to take a turn for Northampton. But Northampton isn't on the way to Norwich. Northampton is pretty much north of London, and Norwich is East. Northampton could only be on the way to Norwich if one started way to the West of Northampton, in which case one would not have been able to get a direct train to Norwich in the first place, as Stimpson intended.
Factual error: There are profound problems with the geography of the U.K. In the beginning, Stimpson is at a train station. He wants the Norwich train, but instead gets on a train bound for Plymouth. There is no station where you could get a train to both. Plymouth is in the South West. To get there from London, you go out of Paddington. Norwich is in East Anglia and you get there from Liverpool Street.