How do I find out what injectors I have fitted ?

Hi folks, how do I find out what injectors are fitted to my Octavia 2.0Tdi PD 8v, (DPF fitted).  My car is missing intermittently and when it does it puffs a blueish white smoke for the exhaust... and the smell is somewhat of unburnt diesel so I assume an injector, just had the loom changed for a new one by VAG specialists locally but I'm thinking it might be easier to fit a new set of injectors than refurbish mine unless you know better or someone nr Bristol Bath who can do the job OR confirm its an injector.... NO fault codes or engine management light yet ! just a bit of missing and odd bit of smoke mainly in third under power... it had a new fuel filter around 3k ago, new injector loom 3 weeks ago, EGR cleaned to within an inch of its life etc

VIN (not complete) TMBKE21Z982239 - - -.

Engine Code BMM

Andy