I recently filled my car with petrol, and as I replaced the pump noticed the display read 46.5 litres. I was sure my tank only holds 45 and it hadn't been empty, but couldn't prove it so paid and left. The manual later confirmed my car has a 45 litre tank and the low fuel light comes on with seven litres remaining, so I had put in 38 litres and been overcharged by about £11.50. I went back to the garage with my receipt and manual, and they were happy to refund me, but convinced I had simply been charged for the wrong pump. I explained that this was not possible as I had first noticed the error on the pump itself, and asked that they have it checked for a fault, but don't know whether they did. I don't know whether this is a common problem, but thought it might be worth a warning to other readers.