Severe pothole around sunken drain

This is a winding, 60mph country road, with blind bends. The pothole is between Passenham and Mill Farm Country Courtyard. The pothole has been caused by a sunken drain cover and as the road is 60mph and a relatively narrow, country road. So that if you are headed toward Beachampton and a vehicle is passing on the opposite side, there is no avoiding it and even below the speed limit, the impact is jarring and likely damaging tyres and could cause a hazard.