Much harder to start from stone cold yesterday than normal, fine on restart when hot. Noticed it was lacking umph at the end of the journey yesterday & it wouldn't run right when I tried to kickdown. Today it wouldn't start at all, flattened the battery & wouldn't start when jumped form a 2.5-16. If I crank it long enough it produsces quite a bit of grey / white exhaust which smells of fuel. Air filter, fuel filter & pre filter changed 3,000 miles ago. Fuel lines charge up immediately & have minimal air, leak off lines on securely, it's getting fuel, it's getting air. Any ideas? P.S. Forgot to say, glow plug light on dash comes on & goes off. 1 glow plug is not working & hasn't been for ages (broke on removal), it's unplugged from the circuit.