I have just added this to the map of places to fly your drone at Drone Scene:
Land owner permission not required.
This is Drum Bridge on the River Lagan, it is part of Lagan Valley AONB. You can walk on the towpath from The Big Fish sculpture (at Donegall Quay in Belfast) all the way to Union Locks in Lisburn. There are plenty of places where you can access the river and towpath. Drum Bridge car park is beside Sir Thomas and Lady Dixon Park - both have large signs indicating what activities you can and cannot do - there is currently no prohibition on flying drone. (Please note that DJI drones will give you Geo Zone warning here but will not prevent flying).
The originator declared that this location was not inside a Flight Restriction Zone at the time of being flown on 21/09/2021. It remains the responsibility of any pilot to check for any changes before flying at the same location.