a common fault with poor cold starting is the injectors leaking back fuel.
The td4 needs pressure to be equal in all 4 injectors before allowing the engine to start. If one leaks back, it gives a low pressure reading and it fails to sart.
One way to test is to spray easy start into the air intake. If it then starts and runs okay, chances are it's a leaky injector.
You can get a garage to do the leak back or leak off test for you, or, if you do a search on here using the search pull down (not the google search box) you can do it yourself with 4 empty coke bottles, a piece of timber to fix them to, and some fuel pipe.
good luck.