When this happened to me, and it was just the way you said it sounded "scuffling and chattering", it was starlings who had got into roof space through poor quality vents under the eaves. Even when new vents had been put over the old mesh ones, they got in through the bathroom fan vents until they were sealed up. I was worried it was something else because the noise would happen well before it got light, but it was birds. That made it easier to deal with because the openings were sealed up during daylight hours while the birds were out. Boy, were they mad! I could hear them afterwards on the roof, chattering and hammering around the sealed up vents.

How high up is your roof? Mine is high because my house is set into a hill so I was less likely to have rodents. Good luck!