if you want flat water, safety bay is the best.
you have never seen a water that flat: like a swimming pool even with 30 knots.

you can kite at the right of safety bay when you look at the sea, there is more flat water and more space on the beach.
you can also go to pinguin island on the sand banc between the island and the shore, but safety bay is better i think
juste be carefull, there is a boat just in the middle of the spot. I saw twice a kite in its mast.
you have to share the spot with windsurfer, because there is a lot of them.
enjoy the spot for me.