I have just added this to the map of places to fly your drone at Drone Scene:
Land owner permission requirements unknown.
Just outside Ballymena, near the village of Broughshane, Slemish has a free car park with a small information centre & toilets (which are temporarily closed due to covid). There are great views from the top even without a drone. It is a very exposed mountain and can often be too wet or windy to fly, which is when your backup (phone?) camera comes in handy.
The originator declared that this location was not inside a Flight Restriction Zone at the time of being flown on 23/10/2020. It remains the responsibility of any pilot to check for any changes before flying at the same location.