Put the tea bags into a jug and pour in 300ml boiling water. Steep for 1 minute, then remove the tea bags. Stir in the sugar and apples. Cover and leave to cool, then put in the fridge for 4 hours or overnight. Strain the tea, discarding the apples and stir in the brandy if using. Pour into glasses and add the mint and some ice. Top up with soda water.