Yeah Dartmoor is a weird case. People release their sheep up on the moors to free roam and they just get so mixed up that some arent really “owned” any more. They are all domestic breeds though. So not like big horn rams or mountain goats.
Plus, feral cats, for example, are still domestic. They were domesticated, that doesn’t change, “feral” just means they aren’t used to humans and act roughly like a wild animal.