Be grateful it isn't right on the horse. But then it wouldn't be would it, as the Horse is owned by the local parish council whereas the surrounding downland is owned by...... wait for it .... the National Trust!
(According to Google searches anyway)
Without wishing to set off an unnecessary geyser (it's only a stupid temporary notice) I wonder if they authorised it, and got paid like at Uffington. Surely not, as they virtually admitted that was a mistake.