[47p2]

017 is the battery number for the A8 and power output seems to range from 88Ah to 100Ah depending on manufacturer. I'm almost certain however that the Bosch S5 020 battery will fit (please check for yourself before ordering) and this beast has an output of 110Ah. They are available from Eurocarparts and there are plenty codes offering up to 30% discount bringing the price a fraction over £93.00 which has to be a bargain for such a battery