You're not from Ponty are you Dai? Welcome to WSF.
Best bait for catching a fish, any fish, down there is mackerel on a flapper rig, plenty of doggies about down there to eat it as well. If you want something a bit more exotic, ragworm under a float from the rocks will get you bass, pollack, wrasse etc. The water was still too coloured up for mackies and garfish when we were there last week, but when it clears up, small sandeel under a float will catch those as well.
Little tip. :secret: shiny little floating beads above the hook when float fishing will outfish your mate.
Float fishing off the rocks, try to maintain a depth that is just above the rocks, you'll lose the odd hooklength but you'll get more bites, also vary the depth often.