Smokey on startup

[Farvs]

A bit of a cheeky first post given I'm starting by asking for some help but would love to hear from anyone who can help with my 'problem'.

My car is a 2005 3.0D with around 50,000 miles. The problem I have is a puff of smoke that lasts for a few seconds when starting from cold. The smoke hangs around in the air for a bit I guess due to being so heavy. It has been suggested this may be due to unburnt diesel though not 100% sure about this. The smell of the emissions on tick-over are also overly acrid. In my 1 year of ownership the following have been carried out:

- 6 No. Bosch injectors replaced
- new cam sensor
- new breather unit
- 1 No. glow plug replaced
- service (think inspection I)
- ECU re-mapped

As you can guess, the above has cost quite a bit and, whilst I love the car, the smoke thing is driving me crazy + I find it quite embarrassing. Most of the above have been undertaken by a highly respected diesel specialist. In addition to the above they have checked the turbo (this was OK) and run with the exhaust + cats off. I am in the UK and the smoking is apparent regardless of temperature i.e. anywhere between -4 and +15 degrees celsius.

The garage have suggested changing the MAF may help solve this although have admitted this may not resolve and are a bit stuck as to what else to suggest.

Cheers in advance