Take it easy.
5 cylinders it has, but only 4 of them have a glow-plug!
They saved a pound a car by fitting only four glow-plugs in a 5 cylinder engine.
I would like to meet the guys who designed this!
So, on a cold start the cylinder without a plug might lag in firing up just for a moment, and then "catch" properly after a few seconds as the cylinder warms up from compressions or because you hoicked the revs up a bit.
It is very unlikely a Delphi injector is causing bother if otherwise the engine runs well.
NEVER put your foot down on the throttle when starting a TD5 as this causes (deliberately) an excess fuel situation that may actually prevent the engine firing up at all, or making it poor to start and very smoky.
CharlesY.