The symptoms on mine are that, when hot, (i.e. after a longer run), it is reluctant to start when turned off and left for 10 mins (like when stopping at a rest stop and rerturning to the van to continue the journey)..it will crank over and over and over,sometimes 10-20 seconds, until it finally starts up..it feels almost as if there is no more fuel in the injection pump, or similar, though there are signs of smoke out of the exhaust as it cranks (possibly unburnt diesel?)...do these have a leak-back check-valve somewhere, to prevent diesel draining from the pump/injectors?
When it is cold, and after the normal yellow light pre-heat (yellow light goes out after about 8 seconds), it is absolutely on the button, starting up instantly..

Would be grateful for any advice.
Thanks.