Smoking Freelander 2

Hi, our friends Freelander 2, 2010, has diesel and exhaust fumes on start up and also when stopping in traffic. After 40 mins driving it gets even stronger and white smoke pours out from under the car on both sides which stops immediately on shut down. LR “ specialist” plugged in and diagnosed turbo. Changed that and no different, so has anyone experienced this fault or got any ideas? Any major fuel leaks should have been spotted when on the ramp?
Thanks guys

Talking to a mate he suggested that if the turbo has gone it will have dumped a load of oil into the cat and exhaust. If this hasn’t been cleaned out or burnt off it will smoke badly when hot. Makes sense?

Have a look under it to see if there's any oil splashed about the eggsauce area or on it.

it could be a Klingon cloaking device