This is good news for a change. I visited Trevethy Quoit just two weeks ago and can confirm there was no livestock in the field and no obvious signs of erosion. Long may it continue.
There has been no livestock since the field was sold June, about 9 months ago now. Prior to its sale the field was levelled out to tidy up the mess that had been made by the horses and some heavy vehicles. You'll be able to see a video of the mess shortly that I sent to EH. It was quite disgraceful