My 57 reg' 2.0T S-Line went through it's front tyres (continental) in a similar mileage to your Mum's; at the time I though it was poor
The replacement Goodyears have lasted better, but they too will need replacing (front) soon and have only done 11k miles. Just a function of the 18" wheels, nose heavy front wheel drive car I guess...
Still, strengthens the case for an A5 2.0T Quattro Cab IMO :icon_thumright:
Peter