Had same problem with fuel leak from my car 320d auto; this only happens when tank is filled to the brim and I had taken my car for an MOT with a full tank which was a mistake as it failed.
BMW were asking £550 and dealer told me BMW UK were not willing to contribute.
I phoned BMW UK and told 'em how disgusted I was as the car had been fully maintained via BMW dealerships.
Totally shocked when they agreed to cover 100% of the cost. Nice one BMW!
