Ahh, ok, well we've seen a lot of that before, usually in the D40s which have a slightly more finicky fuel filter. Here's how you find the fault: in the morning, don't try to start the car, pop the bonnet and start squeezing the primer bulb. It should take no more than 4-5 squeezes to go firm. If it takes more, then keep going and watch the fuel lines - you're pressurising them, and diesel will start coming out of a leak.
Alternatively you might have an issue with the fuel pump or injectors when cold. It's simple enough to see if it improves with some injector cleaner. I've always used Liqui Moly Fuel System Treatment (under $20 at Supercheap Auto) and had good results.