Gowlands Rock

Again, I pose the question - what constitutes a lighthouse? This looks more like a lighthouse than many others, yet apparently it is merely a light. Possibly because the tower has no room, house, shed attached?
On the short 2 mile drive from Kilclief to Strangford, the lighthouses on Salt Rock and Gowlands Rock suddenly appear. This one, Gowlands Rock is on the far, Ards peninsular side, while the red Salt Rock lighthouse is on the near side. They sort of form a finishing line for sailors