Indeed. The thing is, in Japanese they say "Igirisu" for "United Kingdom", and I guess it's often mixed up with "England", which is "Ingurando".
There are also historical reasons, like the Japanese taking the name from the Portuguese who were visiting at the time. "Inglês" ("English" in Portuguese) got turned into "Igirisu" and is, to this day, the word used to talk about the United Kingdom, ("Beikoku" is also used, but it's not as popular) due to the English people having made a name of themselves with their fleets at the time and England being the most populous country in Britain. I don't know if I understood all that right; pretty confusing stuff.
This manga is lovely, by the way. I love bittersweet stories like that.