Seat Leon 5F BJ 2016, 1.4 TSI, petrol odour in the interior

Hello together, The Leon of my girlfriend is having trouble. He has been smelling the first meters at the cold start always very strongly in the interior after gasoline. The workshop said that is normal and you find nothing. But now it is for a few weeks so that the smell is much stronger and he has failed at the pickerl test ÖAMTC/ADAC (HU in Austria). Reason: Very strong petrol smell. The workshop finds nothing – the engine room seems to be dry. The smell in the interior rather comes from the ventilation system, which is why I do not believe that it is the petrol pump under the rear seat. I have already read here that with the 1.4 TSI often the crankshaft housing ventilation or the active carbon filter can cause this problem. I notice that the petrol smell comes from the right side in the engine room (in driving direction). I am not a mechanic, but after some research I have found out what the crankshaft housing ventilation is rather on the (in driving direction) left side. I can not find the active carbon filter. In the internet there is no sign of the gable thing. I have made some comments about the gulf.