Classic case of ". Probably nothing, definitely something". If you ask me. 🙄
Had almost the exact same thing happen at my old place in Woolton about three years back. Rhythmic footsteps, roof, middle of the night. Checked every possible mundane explanation - thermal expansion, birds, foxes - nothing added up. The pattern of it was what got me. Too deliberate.
Few things worth considering:
Check if you're near a ley line. Sounds daft but I've noticed a correlation over the years with properties that sit on or near ancient alignments getting this sort of activity more frequently, Set up a camera. I use a Reolink for outdoor night surveillance now, nothing fancy, but it would've saved me a lot of second-guessing back then, Note the time precisely. These things tend to repeat at the same hour if it's genuine activity rather than structural
What I'd really want to know is whether your neighbours have experienced anything similar. That's usually the first question people forget to ask. Shared experiences in a localised area change the whole picture.
Also - any MiB sightings or unusual vehicles parked up beforehand? I know that sounds like a stretch but there's a pattern there too that gets largely ignored by the mainstream community.
Don't dismiss it. Don't catastrophise either. Just document everything from here on.
What area are you in roughly?