That's just TONS of English period lit, though? Like the only way modern Anglophone writers could get a feel for that way of speaking is basically eating Victorian and Edwardian novels for years. Or a bit later--I think my Five's a bit Brideshead Regurgitated. But there's no real way to develop that except reading the sort of books the people who wrote Three read, especially the kind of cleverer Boys Adventure material they may well have read when they were younger.