TDDI 2003 Cold Start/Idle Misfire Problem.

Alright chaps,

I'm new to the forum and seeking some wisdom, I will try keep this as short as possible but include as much information as I can.

I own a Diesel  Ford Focus 1.8 TDDI estate 2003, currently at 110k with full service history, owned by two families before me who I suspect didn't enjoy revving the car as the EGR was producing clouds of black smoke under hard acceleration, it was also hesitating badly. blanking the EGR solved those problems.

But the problem I'm posting about developed around  6 months ago. The car has a cold start/idle problem, originally it started with a slight lumpy idle on cold start but has progressed to what is now a very lumpy start from cold and a misfiring cylinder when idling (worse when hot).

Cycling glow plugs helps with the cold start dramatically but does not completely remove the problem, I have to cycle them about 4-5 times tho.
The car always starts first turn of the key but it's spluttering, shaking and very inconsistent if I don't cycle the glow plugs more than the usual one time. I also have noticed excessive white smoke on start up, and when pulling away it's noticeable in the mirrors.

The car drives smooth but has a slight reduction in power and fuel economy. Once I stop, say at traffic lights, the idle is misfiring very obviously but clears up and runs smooth after 30 seconds or so.

I'm not a mechanic but I am very hands on, the work that has been done is;

Fuel filter replaced
Glow plugs replaced
Injectors reconditioned
New battery
Timing corrected, slightly out on fuel pump
Cleaned air intake sensors

So before I stop trying to fix it and just drive it until it dies then scrap it, anything I should try?
Really is a shame, as the car is perfect condition minus the problem. No rust, barely any scratches, all service history (I've serviced in twice in the 10 months I've had it) no coolant loss, no oil loss.

Also may be worth mentioning.
I had the injectors taken out by a local garage the second time after I had them reconditioned, so they could be tested at a Diesel Specialist (I thought I may have not reinstalled them properly) they were installed and working fine. The mechanic told me three of the injector's new nozzles were like new but one of them was covered black.

Any help would be appreciated.
Thanks in advance!