Ford Fiesta information display + radio display stays on

After turning the ignition off and locking the car the green Information display on the dashboard and the orange radio display stays on for at least five minutes. Also sometimes the electric side mirror doesn't fold back in when locking the car. I understand the displays are supposed to stay on for a few minutes but does anyone know how long? My garage mechanic said on older Fiestas sometimes the ignition switch doesn't automatically turn off properly. He suggested squirting a little WD40 into the key barrel and turning it through the positions a few times in case it was sticking. - which I did. But the lights still remain on for seemingly a long time.