Now what is interesting is that I do not have those boxes showing on my screen. When I select a location / address I input.... Location....Town....Street/Postcode......House number/Street crossing.
I believe I have seen in navigation settings selectable menu that asks if you want spoken streets in native language, pronounced as local language and various other settings. I am pretty sure there is post code related button. I will over the next few days play around with my system to see if I can replicate and solve, as at present I am in Sicily without the car (foot passenger fast ferry to Pozzallo and car rental ) nice break needed.