The B8 was sold as a 2008 MY car in the UK and Ireland. Tommy's car is a diesel, which is not sold in the USA. For most of the world gas cars have the fuel filter in the tank, and just because of the safety problems with unsealing and resealing a fuel tank, you should let the workshop change the filter. (The service sheet does not mention when to change it for gas cars.)
Diesel cars have two fuel pumps. One is a small pump to transport fuel from the tank to the engine mounted high pressure pump. The high pressure pump is what shoves the fuel into the cylinder. The filter for the diesel is just in front of the small pump. They are in front of the fuel tank. The picture shows it on the left side of the car.
From the manual for Ireland:
If poor-quality diesel fuel is used, it may be necessary to drain
the water separator on the fuel filter more frequently than is specified
in the Service Schedule. We recommend having this done by a
specialist workshop. If water is allowed to collect in the filter, this
can cause engine performance problems.
The manual is silent as to change interval, but in America Audi diesels filter instructions say to remove water at 15/55/95K miles, and replace at 35/75/115K miles.