Hey Robbie, here's something that may help with your battery door problem. With my original P1.1.1, the one I lost in crash, I had an extended battery door that was from a 3D printer. But with my replacement bird, I found I didn't need one and could still close the door with a click, if I was using the Multistar 4000mAh battery. What I did was to notch the left side of the battery door to accommodate the wires (main power plug, battery plug, and balance plug) and make the connection OUTSIDE the bird. This allows the battery to slide in fully and the door will still lock closed with all the wires outside. Then, when you're ready to power up, just plug the XT60 connectors together and you're all set.
One other thing that will help the battery fit better and the door close easier is to trim the excess plastic wrapping from around the end of the battery where the wires exit the pack. Just be careful not to take too much off or you'll begin to see bare solder connections. Hope this helps...