Villanelle's "bird watchers" really do pass by a kestrel (hovering over a field) as their van drives down a hill.
Villanelle's cover when she meets her contact in England is as a part of a bird-watching club. That night Eve is wearing a sleep-shirt with lots of birds on it.
Eve's address is "39 Piscally St, Ealing, London WI3 2CK" (although the postal code is hard to read since it is on the edge of the suitcase tag), Piscally Street is not a real street, in Ealing.
Nadia who has a past with Villanelle calls her "Oksana".
Nadia's cover name, "Fanny", might be a poor choice for a spy who is trying to blend in and be discreet. Although "Fanny" is a diminutive of "Frances", a perfectly normal woman's name, it also has slang meanings. In the US it is a term for the buttocks, while in the UK it is a very rude term for a woman's private parts.