on the demo I had it was a L sat on both the M & L and the L was perfect for me. I needed it for the reach primarily, I'm normally at M on all my other bikes.
it was discussed how to remove battery when flying with bike rather than a vid of how to do. Just do them up British Standard tight then back off a 1/4 turn
I'm sure the torque settings are in the manual
can you drop the motor out and take it from there? I seem to remember it was said on a video undo front 2 bolts and motor will drop to allow you to remove battery.
I'm guessing some sort of internal clip/guides to stop hose rattling about.