Grilled Peaches with Yoghurt and Crumble

• 4 ripe yellow peaches, cut in half
• 1 tbsp extra virgin olive oil
• 1 tbsp maple syrup
• .5 cup Greek yoghurt
• 1 cup almond meal
• .25 cup crushed walnuts
• 2 tsp cinnamon
• 50 g butter, melted
• 1 tbsp maple syrup