The Apple Carplay Activator works!  Simple install, just follow the instructions.  Great job done.  After being turned away by the MB dealer for upgrading our Audio20 on our 2016 B Class (W246) the Braybrooks product gave me the confidence instead of trying some of the dubious offerings on the internet.  Now we have navigation, via the iPhone, through CarPlay, safe and easy.  Fully recommended.