With a potential fuel leak, why be so placid?
I consider a fuel leak to be way above an occasional rattle from trim in how I would approach VW.
You are not sure of there is a leak, so you can't be sure if it is nothing or the car is at risk of catching fire?
This could be a serious issue, I would ask VW to resolve the problem as you are genuinely concerned, if the car does catch fire (unlikely) this will not look good for VW, especially as they recently serviced the car.
There is history with fuel pump leaks on these cars, you can normally see it seeping out of the top of fuel pump body on the rear of the block if it is that.