Used to fish wakanui once a week, weather permitting when I was visiting ashburton. Good beach from october thru to march, use cooked prawn for bait and you should get into some good elephant fish and rig. Have generally found fishes best on nor west or a couple of days after a southerly.
Fished Dorie a few times but always seemed to strike bad days.
another spot worth trying is pendarves. head right down the end of west kyle rd and walk down the gully to the beach, again cooked prawn seems to work best.