I have just arrived back from 3 months abroad and my car is completely dead. My remote door key will not allow me access so,I can use the manual key. Problem is I have no manual key for the boot so I cannot access the boot to charge the battery. Does anyone know how to access or help here ???

This is a common issue with the C Class and your CLK may be enough similar that this procedure will work (go toward the bottom where I included some pictures):

http://www.club202.com/forums/showthread.php?s=&threadid=5771&highlight=jump+start