Where are you particularly at risk during an overtaking manoeuvre here?

You answered correctly. During an overtaking manoeuvre, there is particular risk both when entering and when leaving the wind-sheltered area created by a truck, especially in crosswind conditions. As you overtake, entering the wind shadow of the truck suddenly shields you from the crosswind, and when you leave this area, you can be hit by the full force of the crosswind again. This can cause your car to swerve unexpectedly, so you must be prepared to correct your steering. Awareness of these effects helps you stay in control and safe while overtaking large vehicles.