Dogs don't lie, that's the thing. They pick up on stuff we completely miss and if yours was going mental then something was definitely up there.
Had something similar years back in Derbyshire, heavy footsteps on the roof, slow and deliberate, not like a fox scrabbling about. Never found any prints or damage the next morning which is the bit that still bothers me. A fox or a cat leaves some kind of trace doesn't it.
The black eyed children reports often come with animals reacting badly beforehand, dogs refusing to go near doors, cats hiding for days. Worth noting if your dog stays weird over the next few nights or starts fixating on a particular spot in the house.
What did it actually sound like - bipedal or more like four legs? And how big did it seem from the sound of it? That would help narrow things down a bit. Keen to hear more details from you on this one.