Dave
Having read my earlier reply again, it did not come over as intended.
I stick with what I said, about time at sea and learning from others, but may now have time to help more.
We catch most bream on a two hook rig with a small bright bead just above the hook.
or simply cut a feather rig in half and use that after baiting the feathers with worm squid or bits of fish.
As you say your son wants to target more exciting fish than Mackeral, go to an area that holds plenty and maybe try differant tactics on each rod.
catch a few mackeral every now and then for bait and to keep him busy.
Treat them well [put in cool box] and at the end of the day take those left over home for tea, [they are about my favorite eating fish.] Or freeze a few for winter whiting baits.
Maybe try Southbourne Rough, the outer end of Christchurch ledge on a small tide or the depper water outside of the Dolphin bank
Ref Gear/outfits if you have a selection
try a light one with baited feather rig, bounced back with the tide, or fished "Uptide method"
Mid weight outfit with the rig Barney discribes, or your pennel rig baited with mackeral fillet, fished hard on the bottom for Tope, eels, rays bass etc
and a heavier rod
again just a single hook rig, but on stronger trace line, big hook, whole "Flapper" mackeral, fished hard on the bottom but bounced away behind the boat untill it stops, to await congers and tope.
You will need to look for features and anchor the boat uptide of them to position your baits in your chosen hot spot, it can be tricky. But get it right and the fish will come.
If you get it wrong, do not sit in the wrong place for hours, pull the anchor back in and try a short move to reposition the boat [something we nearly always do when the tide changes direction]
Good luck and very tight lines
Charlie