I have just added this to the map of places to fly your drone at Drone Scene:
Land owner permission requirements unknown.
Criccieth is a Welsh seaside resort on the Llŷn Peninsula that is accessible by bus and national rail. It is very hilly and is difficult to navigate with a wheelchair, but people were willing to help when needed.
On a rocky outcrop above the town sits the castle, originally built by Llywelyn the Great of the kingdom of Gwynedd, but was heavily modified following its capture by English forces of Edward I in the late 13th century.
I took off and landed from the roadside at the entrance to the castle on Castle Street. CADW claim to not allow flights over their property but the castle is not open on Tuesdays and Wednesdays. 
The originator declared that this location was not inside a Flight Restriction Zone at the time of being flown on 09/08/2022. It remains the responsibility of any pilot to check for any changes before flying at the same location.