I have just added this to the map of places to fly your drone at Drone Scene:
Extract from Historic England - "Concrete anti-tank obstacles forming a north-west to south-east line approximately 570m long on the foreshore to the north of Grain village. The line consists of concrete asymmetric anti-tank pimples (truncated pyramids also colloquially known as Dragon's Teeth) in offset rows approximately 1.2m apart."
Amazing these are still there! Worth a flight.
The originator declared that this location was not inside a Flight Restriction Zone at the time of being flown on 11/06/2025. It remains the responsibility of any pilot to check for any changes before flying at the same location. Landowner permission may be required before taking off.