Poor cold starting followed by misfire / erratic idle symptoms with slight exhaust emission???

Can be really bad to start sometimes & can have to crank for 30 seconds before engine running!!!
It seems to give a starter kick back symptom & kerr-ching noise from flywheel area as you crank, that tells me possible timing issue!!!

As vehicle warms up symptoms iron out & vehicle runs smoothly & restarts with no problems.

Tested all glow plugs out checked O.K!
Assuming glow circuit on time is correct at 10 seconds on time after start up! (does vary according to temperature)

No fault codes in system!!

Timing belt & injection pump belt have been replace not to long ago by another party!!!

Suspect a timing issue or crank sensor issue!!

Any pointers???