Bring the tea to the boil, steep well and allow to cool slightly. Add the sugar to the tea or stir well into the drink later. Add the pomegranate syrup. Pour the tea-syrup mixture into a container or carafe. Squeeze the oranges and mix in. Pour in the brown rum. Add the pomegranate and pumpkin flavours. Top up with the Prosecco. Use the orange slices as decoration and enjoy chilled with ice cubes in the glass.