I have just added this to the map of places to fly your drone at Drone Scene:
Land owner permission requirements unknown.
A well hidden dilapidated mansion just a short distance from Beaumaris castle.
It can be flown from Castle Car and Coach Park (w3w supposes.historic.dorm) but it’s around 1km so you need a clear day and good signal. Alternatively it’s around 500m flight from any of the layby’s on Henllys Lane (w3w choppers.stocks.silent).
On foot it can be explored and is accessed by a track near the bridge over the B5109/Allt Goch Fawr (w3w shepherdess.tycoons.enchanted). It’s walkable from the main car park but easier to park on one of the side roads nearby.
The originator declared that this location was not inside a Flight Restriction Zone at the time of being flown on 30/08/2018. It remains the responsibility of any pilot to check for any changes before flying at the same location.