Nissan Note Diesel Exhaust noise

[Beautiful South Martin 24]

Sold a  2014 Nissan Note 1.5 DCi to a customer who rang after 1 day of ownership to say the exhaust was blowing, got it back in and my garage guy has stripped the entire exhaust off to the check the manifold, done smoke tests etc and is adamant there is no issue with the exhaust. It does sound exactly like its blowing from the front of the car when you put the revs on. Any clues anyone?

Thanks

[Halfpenny 114]

There is a problem on these whereby the airbox plastic fasteners break causing a rasping/vibrating noise usually heard accelerating in 1st, 2nd....sounds like exhaust.  New airbox needed.