I have just added this to the map of places to fly your drone at Drone Scene:
Land owner permission requirements unknown.
There is a free (2hr) car park at the base of the castle. The land is owned by national trust.
The originator declared that this location was not inside a Flight Restriction Zone at the time of being flown on 11/09/2020. It remains the responsibility of any pilot to check for any changes before flying at the same location.