I tend to be more of a reader than a writer in Harry Potter fandom

Me too ... I think I'm intimidated by the possibility of messing up British-isms. I've actually written two HP stories, but they were for challenges that rather narrowly dictated the characters and premise, and while they were fun to put together, they didn't come from an inspired place. Sometimes I even forget that I've written them. But if I ever write one more spontaneously, without parameters set by a challenge, Lupin will likely be involved!