Nice fish for the speicies concerned.
Further North those sizes are common. In the Durban region the average is probably 20cm. Abundant in the shallows of the beachfront during Summer. My biggest is just over the 1.5kg , they get bigger and can pull you flat at times, particularly when there are a lot of them. Prawn and chokka combo works well.
Dropshot and fly fishing for them also produces results.