No spoken turn by turn directions with Maps on iPhone 5

Hi I just recently purchased an iPhone 5 and was keen to use spoken directions with turn by turn when using maps.

However, I can not get it to speak the directions and there does not seem to be an option to turn it on.  I have ensured that I have an accurate current location & destination.  I have the icon for car highlighted.  I then press the Route button and it shows the direction clearly on the map, but when I press Start I only get the visual green signs and no sound.

I have checked that Map settings has Navigation Voice Volume set to Normal and have also tried Loud.

Am I missing something?  I am in Australia, and wonder if we don't get this feature?

Help appreciated.