Millstone

During Lockdown I've been doing a little local research and learned about the Gunpowder Mills in Ewell. I read there was an original millstone on display in a local park. I set out today to find it.  It didn't take too long. It had a plaque on it with the inscription "Millstone from the nearby gunpowder mills on the Hogsmill river. Founded c.1775 and closed in 1875."