sat nav woes

Sorry if this is covered in a different thread but I am new here.
The sat nav in my 07 reg freelander hse seems very out of date.
My parents live in Devon.
So I went to destinations.
The Postcode. I entered PL19 but that was as far as it let me go.
Are you seriously saying that the sat nav does not support full postcodes or is this just an upgrade that I need - and will the LandRover dealer where I got the car supply it.

So you need pratt nav to get to your parents house?
Not much of a son are ya!