This is a piece of fossilised coral imprinted in limestone. Notes on the area say it is likely 320, million years old. We're not great at fossil identifications here. If you are, and you know more about it than us, then feel free to let us know on TikTok. 
This is a really pronounced circular coral. Horn corals existed in this area. This one has visible spines and brilliantly preserved detail. It's from Lothian on a recent trip.