Sorry, I forgot to post an update. I did "p38owners" suggestion and it worked a treat (cheap too). Thanks everybody for all you help.

Thanks for the suggestions. Fitting a one way valve sounds like the best plan. The problem certainly appears to be fuel draining back. Many thanks, Andy.

Hi, I'm new to the world of 4x4 and also diesels. I've just bought a 1999 P38 2.5DSE which has an odd fault that I hope someone may be able to shed some light on. The car runs great and drives very well for such a big beast. Unfortunately when I start it in the mornings it's not to keen to...