Been following this thread since you first posted. Living out on Dartmoor I get all sorts up in the rafters - jackdaws, the odd squirrel, once what turned out to be a barn owl that had found a gap under the eaves.
But that footage you posted last night... the movement pattern is odd isn't it. Animal movement tends to be purposeful, they're going somewhere or looking for something. Whatever that is seems to be just sort of hovering in one spot for a while.
Could still be something mundane. Bad night vision footage does weird things and pareidolia is real. What does it actually sound like? Scratching, footsteps, dragging? That would help narrow it down a fair bit. If you can get a clearer clip or even just a better description of the sounds that'd be useful.
Not saying its anything paranormal but I wouldnt dismiss it either.