Stalls when cold, fine after a few miles. Stops when hot and wont restart.

Its the 1.7cdti engine.
wont tick over when starts. When warmed up after a few miles it runs fine. If get stuck in traffic though it tends to just die and wont restart. Sometimes will re-start after remove and plug back in the 2 main plugs on the rocker cover
had new fuel filter
new crank position sensor
tried unplugging the maf sensor but it made no change to way it runs so unsure if it has a fault
had new fuel pump just before I bought it (600 quid so pleased I didnt have that to pay for)
done pedal test to get flash codes but it shows as having no faults?
its a high milage van but had new bottom end before I purchased so still worth looking after
any help would be a bonus as get lots of different answers from weekend experts so need someone who knows there stuff lol