And I think it's my recently deceased dog.
Dog died about six weeks ago, was a young dog. I have another dog left and two cats.
About a week ago, me and dd and dog were upstairs. Me on the landing and dd in her bedroom with the door open, talking. The dog was in her bedroom. I very distinctly and clearly heard the noise of a dog charging down the hallway, scrabbling on the wood floor with claws out. Just like both dogs did (one still does). I immediately leaned over the bannister and no sign of anything. Dd came running out her bedroom as she had heard it too. I ran down the stairs into the hallway and then straight into the dining room.
Neither cat was in the house. As I got into the dining room I looked out the patio doors to see if a cat was running down the garden and couldn't see one. But I really don't think it was a cat. It was too heavy for a cat, the cats never scrabble on the wooden floors, I didn't hear the cat flap go which im sure I would have done, it's very loud. There was no sign of a cat in the garden and they can't get out our garden at the sides due to high walls so always run 100ft to the garden end. It's all lawn, no shrubs to hide in and there was no cat. Door to the front room was shut so they hadn't gone in there.
Today I had nearly exactly the same. Sat in the front room with a friend chatting. Heard exactly the same and it sounded like it was coming towards us. Friend said "have you got another dog", my dog was on the sofa with me. I jumped up and straight into the hallway which was empty. Searched the house and no cats in the house. Nobody else in the house at the time.
I'm not imagining it as two other people have heard it.