I have just added this to the map of places to fly your drone at Drone Scene:
Land owner permission not required.
Parking on the B133 Millvale Rd near Bessbrook, or at the small car park on the Craigmore Road (under the main A1 Belfast to Dublin). There are several public footpaths in the area where you can get views of the viaduct.
The originator declared that this location was not inside a Flight Restriction Zone at the time of being flown on 07/09/2021. It remains the responsibility of any pilot to check for any changes before flying at the same location.