The kitchen scene with Eve and Villanelle was previously used as Jodie Comer's auditioning scene with Sandra Oh. Just like in the actual scene, the audition required a lot of food to be eaten, for which Oh brought some prop food, like blueberry pie (from which Comer almost ate the entirety of while auditioning).
The Russian prison record for Oksana Astankova (Villanelle) lists her patronymic name (Russian "otchestvo") as Anatolyevna. Most Russian people have a patronymic name in addition to their first and last names. The patronymic name is constructed from the father's first name + a male ending ("-ovich" or "-yevich") for a son or a female ending ("-ovna" or "-yevna") for a daughter. The endings mean "son of" or "daughter of", respectively. Since Oksana's patronymic is Anatolyevna, this means that her father's first name is (or was) Anatoliy. Also, Russian last names have different male, female and plural endings. Oksana's last name is Astankova, which ends in "-a" because it is a female form. If her father shares (or shared) the same last name, then his last name would be Astankov.
The "SVR" is also known as the Foreign Intelligence Service of the Russian Federation and succeeded the KGB First Directorate as the government agency responsible for intelligence and espionage outside the Russian Federation. The FSB is the more commonly known agency in popular culture, and, like the defunct KGB Second Directorate, is the one responsible for monitoring activities and people inside Russia.
The prison record states that Oksana/Villanelle was born on 12.03.1993. This is one day apart from Jodie Comer's actual birth date, 11.03.1993.
"Brown sauce" is a popular condiment in the UK, and is usually called "steak sauce" in the US. The most common brand is H.P. Sauce. It usually has some combination of molasses, tomatoes, vinegar, and tart fruit like dates or tamarind.