Brew the tea in the boiling water for 5 minutes. Set aside to cool down before putting in the fridge to chill. Place the diced mango in one freezer bag and the halved strawberries in another and freeze.
Once everything has chilled down, place the 250ml of the tea, mangoes in a blender and top with a handful of ice. Blend together and pour into a jug. In the same blender add the remaining tea, frozen strawberries, honey or agave syrup (if using) and a handful of ice.
Starting with the strawberry slush and spoon into glasses. Top the strawberry slush with the mango slush. Serve with straws and garnish with a piece of diced mango and half of a strawberry.