Factual error: The family stays briefly in a British apartment, however the plug sockets displayed are US standard, not UK.
Factual error: When Lois, Meg, and Chris go to the stage show on the West End, "theater" is spelled with the Americanism "-er" instead of the UK spelling "-re."
Answer: Mort is Jewish, and Walt Disney was said to be antisemitic. So it would make sense in a Disney universe all the inhabitants would share his supposed beliefs.
MasterOfAll