I believe that if you still have coolant fluid showing in the header tank then its as per normal to top up to the given level ( also consider that the level should not have dropped, so something is going on ). The issue of bleeding will occur when the header tank empties completely and air has been drawn into the system.. Most likely at that point it needs specialist kit to bleed the air out??. I dont have any first hand info about bleeding the coolant system, but when I get to speak to our dealer I will certainly be asking. To my knowledge there is nothing in the owners handbook that highlights this.
