Make strong tea using the tea bags and boiling water. Add the sugar and half the mint. Allow the tea to infuse for 15-20 minutes, remove tea bags and leave to cool. When completely cold, remove mint. Add the orange and lemon juices, and the remaining mint, to the tea. To transport to a picnic, remove mint and fill water bottles with the mixture. Dilute with cold water to taste, and freeze or semi-freeze. Add mint and fruit slices just before serving. Serves 6-8.