This is a great story. You're writing is crisp and flows at a natural pace. I like that you are pacing the story slowly. Too many fanfic writers just jump headfirst into the pool of fluff, and the end is not really earned.
Jenkins is a creeper. It is eerie how you write him -- supposedly kind and warm, but with a darker side clearly lurking underneath. I suppose that's how it goes, isn't it? Also, I'm curious as to the choice of the name. Was it random or does it mean something? My first thought was that it sounds like Jekyll, which is quite appropriate.
Also, I don't think Harry is OOC, at least, not relative to most fanfics. He feels like a twelve-year-old boy, which is hard to do. Most writers seem to make him too young.
I hope you keep going with this story, it's great!
Author's Response: While I actually now love the comparison to Jekyll, I'm afraid I wasn't quite that creative in picking a name. To be honest, I just wracked my brain for a nice, common English name that wasn't Smith and had never (as far as I'm aware) shown up in Harry Potter before; and thank you so much for the compliments, both on the pacing and the characterizations! Trying to write a twelve year old is extremely difficult because it's that awful, awkward age between being a child and a real teenager. I'm glad you think I've got it right.