i have exactly the same problem checked the earths on the motor all seem ok some one sain if it does it again in winter try an extra earth cable from the batterie negative sid too the engine if it starts well then it is the earth other wise it is the drain the only drain i have is my allarm system from landrover as standard .so i am going too get the maximum cranking power i can get which is an exide premium battery if that dont work then its plan b A VERY BIG HAMMER good luck .