Unfortunately I no longer have an owner's manual to refer to and the online version I have has different page numbers to the one in the car, but it is in the set-up menus for the navigation. For example, when I first had the car I asked it to take me from home into Glasgow, the system gave me 3 routes but none of them was the route that I would normally take. With the "learning" function on I drove the route I would take and from then on if I asked for guidance for the route from home to town it would give instructions along the route I actually drive. It can back fire too - after taking delivery I drove north from London to Scotland with the mode selected and pulled into both Keele service and Teebay services..................... ever since it has directed me into those two services whenever I have driven north as I never found out how to undo a route!
Edit - the function above is called "Learn Route" and here is the page from the online manual in Topiz
Quote:START GUIDANCE
After touching Destination, the system will
calculate the route.
There is now a choice to select 3 Routes,
Change route or to Start navigation guidance. Touch 3 Routes to display a choice of three
different route options on the map.
The roads on the map are drawn in three different colours to highlight each route. Leaves are used alongside each of the three calculated routes toindicate the most fuel efficient.
Three full leaves is the most efficient.
Select route 1, 2 or 3 by touching the respective box displayed on the right side of the map.
Touch Change Route followed by Route prefs. to change the route settings. If a destination is already set, touch Waypoint to add a waypoint in the journey if required.
When you have made your selection, if any, touch Go.
Note: As you approach a junction, in addition to the voice guidance, an inset on the map will display an enlarged view of the junction.
STOP GUIDANCE
To stop route guidance, proceed as follows:
1. Touch Nav menu on the map menu screen.
2. Touch the Stop guidance soft key.
EASY ROUTE
In Route options, Easy route can be turned On
or Off.
When On is selected, Easy route changes the calculation parameters of Route 3 in order to reduce:
• Junctions.
• Turns.
• Turns that cross traffic.
• The priority of minor roads.
• Complex junctions and manoeuvres.
LEARN ROUTE
In Route options, Learn route can be turned
On or Off.
When On is selected, if you make the same deviation from the proposed route three times, then the system will memorise the deviation and offer that as the normal route from then on. Select Reset all routes to delete any learnt routes and return to the default settings.[/bold]
VOICE GUIDANCE
To turn voice guidance on or off but maintain route guidance, proceed as follows:
1. Touch Nav menu on the map menu screen.
2. Touch the Route voice guidance soft key. The soft key will be highlighted when voice guidance messages are enabled.
QUICK POI SELECTION
Touch the Map screen to display the POI button. Touch the POI (Point of interest) button. The screen shows six suggested categories, five of which can be selected as quick points of interest.
Note: The POI icons will not be shown if the map zoom level is greater than 1 km (1⁄2 mile).

The above is page 154 of the on-line owner's manual, I'm not sure if it is the same page number in the hard copy
For those having problems with strange routes being given to them then try using the "Easy Route" setting described above and see if that makes any difference as it has "built-in" filters for calculating more efficient routes