I thought i'd stick this post on in the hope it may help someone with the same problem.
My 2.5 diesel was a pig to start, it would turn over for an age and then start with a good puff of smoke, it made no difference if it was hot or cold although it was worse with less fuel in the tank.
I bought an in tank fuel pump from Ebay for £42, it was a easy job to do although i did have to drop the tank, a couple of hours work and now it starts first touch of the key with no smoke at all, bloody marvellous.