I have just added this to the map of places to fly your drone at Drone Scene:
Land owner permission not required.
I didn’t think much of Calshot castle however it’s a great place to get footage of ships coming into Southampton docks
The originator declared that this location was not inside a Flight Restriction Zone at the time of being flown on 03/07/2021. It remains the responsibility of any pilot to check for any changes before flying at the same location.