RNS E sat nav not th best?

[Triple.O.G]

Hi guys, on my sat nav when you try to enter a postcode it will only let you put in the first 5 digits? is this correct?
its fine if you have a sreet to put in but if your going to say an industrial estate its alot harder to find where you want to be. also if i take a wrong turn on purpose for road works it wont reroute, is this a functin thats turned off or it just doesn't do it?

Thanks in advance.