Fuel Smell - A-160 ACS

Really need some help please guys.

I have an A160 just coming up to 4 years old. I have been getting a strong fuel smell inside the car, normally soon after it has started. The smell is also strong on the outside of the car.
I called out the Mercedes Mobilo technician and he could not find anything wrong with the fuel lines under the bonnet, and said I would need to get it booked into the workshop.

I have seen this problem listed on another forum as an
Airflow / Engine management system fault. My dealership are not aware of this problem and want to charge me huge amounts of money to investigate other areas.

This according to the other site was a common problem with the A-Class and needs a replacement airflow/engine management system.

Is there anyone with knowledge of this problem or even better access to the Mercedes common faults database that could give me some kind of reference number, so that I can better describe this to my dealer to ensure it is covered by the warranty I took out.

Many thanks in advance for any assistance.

Martin Wood