Sony NAV-U51 Map Update Question

Ok im a new here so hello to all.
I recently purchased a NAV-U51 and am very pleased with it in general, but I have one small map issue I do not understand.
Some streets and road modifications are not on the system, my road for example is fairly new its not there and some of the POI are showing petrol stations where houses are now going up!
How is this information updated on the sat nav? I did the software update off sonys site, that didnt help, are there map updates available as well?
Sorry if its a stupid question, but surely as the unit gets older and more road modification occur then the maps should improve, like a road atlas renewed each year
Thanks in advance

 

It should improve, but it unfortunately does not always work like that.

I have a TomTom, and even with the latest maps it still does not recognie some road systems that have changed 5-6 years ago.

 

No map update for your unit yet as it is too new.

The map update for the older U50 costs £90 from Sony (but includes all Europe).

Sometimes it is cheaper to just buy a new unit when the maps are old!