The problem with Flat rock is the hight you are above the water. Its a good 15 feet up which means a very long gaff or net should you manage to get a fish to the face.
Its not deep directly at the face either, there is a lot of rocks and weed to drag your fish through before you can get at it.
It might be 30min in your running shoes carrying a water bottle, but with rods, bait and gear, closer to an hour. A lot of the track has slipped away and much rock-hopping is required.

The staff of fishing shops always tell tall tales of fish being caught here, there, everywhere. How else are the going to entice you to buy stuff!

(disclaimer: of course we know that Phil, Kane and Neil always tell the truth, but as for the others...)