Diesel poor starting from hot

[sniff petrol]

When my BMW 325tds is cold it starts really well but when it's warm it takes several turns and up to 8-10 seconds of turning it over to start up. The warmer it is the worse it is at starting basically, so if I let it cool down for a couple of hours it starts alright again. What could be causing this? I'm thinking some thing's getting hot that shouldn't be. Many thanks for your help cause this one's turning me mad.

[VYT]

Is it a common rail engine? If so I would hazard a guess that the fuel pressure is low.

[sniff petrol]

Nope, just boggo standard indirect injection.