Since it's not strictly an error in the Alpha document, figured it's best to create a separate post for this.
Mythic Britain and Ireland or Britain and Ireland is fine, but using British Isles is an extremely loaded term, as you can find on this Wikipedia page. In particular, the popularisation of the term following the Act of Union to create a sense of "Britishness" in the Irish people.
Given Vaesen has always emphasised mystery and inclusive roleplay over pure historical accuracy, it's important to flag a term that will irk Irish players (like myself).