You do... Before every time you go abroad and (naturally) when you come back, too.
You have to go into the dealership and rant how shortsighted BMW is. When you have finished ranting, the youth opportunity monkey will take you gently by the arm, walk you to your bike and point to the KPH figures alongside the MPH figures, on that round bit with the whizzy arrow arm bit, next to the screen bit with figures and fings on. He'll then point you in the direction of SpecSavers to get YOUR shortsightedness fixed.
