Audi A6 2.5tdi Quattro Failed MOT on bits I expected it to garage to sort those bits.

Passed emmisions test however it failed the visual emmisions due to being smokey when oil temp at 75 degrees and above?
although I had the car running for almost an hour last night and could not see any smoke at all?

Car had been stood for about 7 mths could this be the cause (not done an oil change yet)

I have checked the oil breather filter (mist seperator) no hissing when loosening the oil filler cap.

Timing is within limits slightly retarded from the middle line (should i advance it a little?)

could it be the egr valve? the intake manifold feels quite hot?

any ideas welcome...