Anji's car has a road tax disc which have not been in use in the UK for several years.
When Anji and David bump into his girlfriend and mother, in the shop he steals the necklace from, his girlfriends mother says that when Anji was a kid she would insist on going to a Christmas market every year, to have a hot cider. In Britain hot cider is alcoholic like mulled wine so, it's not normally drunk by children.
Anji's address has blvd in it which is not commonly used in the UK if at all.
When they leave the department store with the necklace, they are standing on Piccadilly at the entrance to the Piccadilly Arcade (where they go to the shop where they are holding a silver pen for Anji). As they flee security, they go east on the south side of Piccadilly, then cross the street and go west on the other side of the street. They backtrack to go into the courtyard of Burlington House.
When Anji parks across from the Landmark Hotel, her car is in an area marked "no parking after 9pm." When they arrive at the impound lot, the sign says it closed at 9pm. The car was parked legally until 9pm so they would not have been able to take it to that impound yard.
Generally in London, people do not talk to strangers at all and especially on public transport. It is one of the unwritten rules of social conduct in London.