If it was a mercedes I'd say that one of your injectors was leaking off and for you to have a leak-off test done (an hour or two labour from a diesel fuel injection specialist). Its quite common on the mercs causing, amongst other things, poor hot start. Apparently the
can't build up enough pressure to fire up, but once running will run like usual.
A tell-tale sign of this is air bubbles in the diesel return pipes.
Worth considering maybe.