Still if you enter the street number in it knows whether it's on the left or right... those postmen have big postman's walks even bigger these days with their trolleys (let Saggy play with that). Postcodes are good for posting letters but it does have geocoded addresses in it which are more accurate than postcodes with auto fill boxes. So you don't need to use postcodes... be a rebel.
Anyhow we were going to a service station in Belgium off the main road, granted there were road works which it got off trafic data, it took us off a side road, round an industrial estate and stopped at the back of the service station across a field. Think we were supposed to put are hiking boots on and make our way on foot. I think it decided the slip road was closed from the trafic data and did the next best things. So retraced the drive and a bit more and the slip road wasn't really closed just a bit off piste.
All my imported coordinates were fine on the road trip to Germany bar that one and an industrial canal tour in Dunkirk where I obeyed satnav but should have ignored it. Still I know the route to buy AdBlue in Auchan, from the port now through the back roads. The red, blue and orange routes are quite different. Locally one picks the shortest but driving large distances you want the fastest, when things go weird picking the back roads. The satnav can be turned off so it doesn't offer this choice, it's this choice if you get it wrongs leads to problems.
Edit:
Right then Bob the problem with the street Ravenscroft in Hook that has that postcode is that they don't have the house number street level mapping, so you only get the junctions offered up. I can see that since it's a new street the database they are using for street level mapping isn't up to date, so the cracks in the system can be seen. This is based on the Navigation Plus system but I'm sure you would get the same results with the standard system, 2016 maps. QQ doesn't work on my system so I don't what that is about.
Afraid my choice way of getting exactly to geo locations is to use the x,y coordinates because the system uses DMS you have to convert these and dial them in or use an app where you can find these and enter them in or bulk import for POIs. I will be using the latter method for future holiday destinations which is how I ended up importing 126 destinations from Co-Piolot. Make the POIs via import, select POI then make it a destination. Then you have destinations marked up on the map as POIs plus as proper destinations in the car's system.
Most car systems use DMS so this issue exists unless they have got into bed with say Tom Tom. Older residential streets which have been geocoded at a street address number level you can do it that way and bypass the postcode entry method. Industrial estates I found problematic when I started entering in the postcodes since one postcode can cover a large area and street numbering doesn't exist in these places.
I can see why people may opt to use Android Auto but then you don't get the lane guidance details and you do need to be connected and it does bypass the plus side of having the navigation system integrated with the turning wheels so if satnav connection is lost the cars system is better at knowing where you are than a stand-alone system.