99 1.9d won't start after running at temperature ?

[Bman16]

Hi, I have a 1999 1.9d berlingo van which after driving for half hr or so and reaching tempertature drives perfectly. The problem occurs when stopping and turning off the engine! I try to start the van again but it doesn't do anything, the relevant lights appear and go off as usual but van won't even tick over ?
I have to wait for the van to cool down and reach a starting temperature or there abouts for it to spring back to life. Any suggestions would be very much appreciated ?