Relay van smoke

[pogo001]

Hi.
I have a 2008 Citroen Relay 2.2 hdi van. I have changed all glow plugs and the van starts on the button always. When I start the van from cold, it erratically misfires a little and blows out a lot of blue smoke, smelling like diesel smoke. If I raise the revs, its clears, or if I drive off it clears. When the van is hot, it starts and runs perfectly, good mpg, passes emissions tests, and no smoke white or black. However, if I drive it a little, and its luke warm, then I start it, its embarrassing with the smoke it pumps out until I rev it and drive off. Warm starts are by far the worst.
Where I live, in rural France, I dont often have this problem so have lazily lived with it for too long. Diagnostics showed that injector 2 was at fault. I changed this, and was let down last minute with re programming the injector, but the problem was exactly the same, I expected to see a little difference before re programming.
Does anyone have any ideas? Im doubtful that the injector is at fault, or could simple reprogramming be the original cause of the problem, and what could cause the correct setting be suddenly lost? (the van was in an accident around the time of the start of the fault.
Thanks for reading the waffle.