South Rakaia and Dorie beach may be worth a try. In the past Dorie has been the best place I’ve fished for big School sharks, although this year seems to be more small ones about. Lots of skate and rig around this area as well. Nape Nape is also good, and about the same distance from Christchurch as Birdlings etc depending on what part you’re in. Skate/Congers/Rig/Schoolies and even Gurnard caught there.