[Fanfiction, Sherlock, Request] Needed: Beta and Britpicker or Pointed in the right direction

I've gone ahead and started writing a massive Sherlock Hunger Games AU, because my life sucks more than usual right now and writing is therapeutic. Also, the idea has eaten my brains. In the middle of the prologue (which I posted in chunks on ye ol' tumblr), I realized that this was serious business and I would most definitely be finishing it - even if it takes me two years and thousands of hours of my life - and my aspirations for this fic are to share it with a wider audience for their enjoyment, so I will most definitely need a beta and a Britpicker - ESPECIALLY the Britpicker. I'm writing the Capitol accent as British, and no matter how much BBC I watch and how many well-crafted Sherlock fic I read (by actual British authors), I'm going to make mistakes - some of which will be very embarrassing.

How does one go about acquiring a beta and/or Britpicker? I'm still a bit new to Sherlock fandom, and as with Supernatural fandom (outside of challenges), I keep to myself mostly, so I don't know too many people. I kinda have this anxiety about participating in communities, mostly because I'm afraid of stepping on people's toes. I'm clueless to how fandom operates outside of my own small corner D: (Seriously, I'm looking at sherlockbbc and whimpering because it's so intimidating!)

Or, better yet, can anybody recommend small communities, so I can test the waters of fandom participation?

(Ugh. I'm so pathetic. I need to man-up)