Andy, the snapper fishing at arapanui can be excellent. But the best fishing for them is from 7:30pm to 8:30pm. Over the past 3 years I have pulled out some fantastic fish from there as well as big trevs, kings, and plenty of big sholies.
Fish on the southern side of the river mouth 2/3rds of the way down the beach. there will be a good hole where the old mouth used to be, thats where the fish will be.