When is Journey to the River Sea set?

Question

Eva Ibbotson's Journey to the River Sea is a novel set mainly in the Amazon region of Brazil. It's clearly set quite some time before its publication date of 2001, what with a "governess" being a major character; but it must also be set after the 1880s, given the existence of Little Lord Fauntleroy as a stage play in the story. Wikipedia says it's set "early in the twentieth century", but gives neither a source for this claim nor a more specific period.

When was the book set? Let's see how narrow we can get the range.

Answer 1

It's set in 1910.

For while the sisters prized proper learning, they also prized good manners, thoughtfulness, and care for others, and the girls learned both algebra and needlework. Moreover, they took in children whose parents were abroad and needed somewhere to spend the holidays. Now, some thirty years later, in the autumn of 1910, the school had a waiting list, and those girls who went there knew how lucky they were.

(p. 1, ch. 1)