number of litres, cost, mileage covered all fine by me, that way doesn't matter if you miss the odd one...

Just remember when you sell the megawebsite " truecardata.com" to the AA/RAC for £200 million where the idea came from

think about it though, you are looking to buy a XXXX YYYY and can see teh 'real world averages' and running/repair costs, that woudl be awesome!