audi 2.5 tdi s line smokeing from cold help

hi all audi people i have a problem with my audi sline its a 2005 tdi v6 2.5 with 85000 miles i seem to be getting loads of what smells like unburnt diesel out of my car from cold its greyish colour when i start the car from ccold it start pumping out this smoke untill what i think the cold start kicks out it runs a bit lumpy as well as soon as the cold start stopd the engine idles nice the smoke clears and fine no loss of power i had the car into audi left it with them overnight and they had it all day went to collect they said nothing wrong with it spoke to the tech and he drove it left it to cool even stsrted it while i was there nothing like it was fine now i work on ships so it get quite cold on the docks it seems to do it ll the time to me i said to the tech is it injectors etc he said no as it would show some fault on the computer and there was nothing so i had it serviced new oil filters air filters glow plugs and it still doing the same any help would be good

hi thanks for the reply just been and bought some red x see if that helps its doing my head in love the car but if it carrys on going to get rid