I have just added this to the map of places to fly your drone at Drone Scene:
Land owner permission not required.
Parking and TOAL from Pont ar Daf car park.
Beacons Reservoir is the northernmost of the three reservoirs in the Taff Fawr valley in South Wales. It was built by Cardiff Corporation Waterworks between 1893 and 1897, and the water is impounded by an earth dam with a clay core. Since 1973 it has been owned by Welsh Water.
The originator declared that this location was not inside a Flight Restriction Zone at the time of being flown on 22/01/2022. It remains the responsibility of any pilot to check for any changes before flying at the same location.