A Lightly roast the macadamias in a dry fry pan over a medium heat until light golden brown, shaking regularly and watching carefully to make sure they don't burn. Alternatively pop on a tray in the oven on medium heat - again watching carefully to make sure they don't burn.
In a small saucepan melt the cacao powder, coconut oil, agave syrup and sea salt together over a very low heat - continually stirring, until well combined. Do not let the mixture boil - remove from the heat if it's getting too hot.
In a shallow, non stick, baking dish pour approximately a third of the chocolate mixture to cover the base of the dish. Place the peach halves on top, spacing evenly apart to line the dish, sprinkle over the macadamias - lightly pressing them down in to the chocolate.
Pour the rest of the chocolate mixture over the top of the macadamias and peaches. Pop in the fridge or freezer until set before running a knife around the edge to pop the chocolate out of the non-stick tray.