Sat navs can only work to the data in the map. I have the Garmin Camper 760 but the map data is the same on all models. The width of many minor roads are not yet included so it will still direct a wide vehicle down them even if it will not physically fit. Map updates are always an improvement but it's still always best to scan the route before driving it, I learnt that after being uneccesarily sent down some extremely tight lanes a few times. So you never quite know with road widths but I would at least like to think that height restrictions are accurate and complete!
I also noticed that even after the latest update on my last trip that some speed limits were either 10mph over or under, not sure if car mode would have been different or if the speed limits had recently changed for that particular road stretch? But generally it seems okay!