I have just added this to the map of places to fly your drone at Drone Scene:
Land owner permission not required.
Easy parking in numerous areas around the castle. There is a handy small free car park just over the River Clwyd bridge on the Western side on the left near the traffic lights. I flew from the pavement at the side of the road, VLOS to the castle (sub-250g).
The originator declared that this location was not inside a Flight Restriction Zone at the time of being flown on 23/11/2021. It remains the responsibility of any pilot to check for any changes before flying at the same location.