I beleive the wharf is public… I beleive the council made it.
I think I know the points you mean which are before te mahia but have never figured out how to access them from the land. Have spent a bit of time Kayak fishing around them and someone did try to explain the access to me once but I was to slow to comprehend/remember it. I am certain I could figure out how to access them if I tried.
The spot in Broughton Bay I have fished (well known spot) is you park just near the big trees and walk down a short track to the beach. There is a old Boat-shed 25m or so to the west. Alternatively one can walk down the track to the boat-shed to access the beach but the land there is technically private. Back when I was a kid my father had quite a bit of luck there but I have blanked the few times I have tried it.
Think I might try and access the point between Te-Mahia Bay and the triple pointed point. Looks like only a short walk from the road with no baches to walk through.