hollymay

I've got a 2005 A8 3.0L Diesel....and because I've only been doing relatively short journeys recently on top of the cold weather I had to call out Green Flag the other day when it wouldn't start. They successfully jump started the car.....and then tested it and came up as a 'pass' but only at 53%. Although I've been out a few times since it still seems a bit iffy, particularly first thing and I don't fancy the prospect of being out at work this week and it happening again.....so I went down to Halfords today to ask them to test it again and then hopefully recommend a new one. The guy put it on his tester and it kept coming up with an error sign.....and he said that it was indicating that something was 'taking something out of the battery' despite everything being turned off with the door locked. There are no interior lights on and there's nothing else I can think of that would cause such a problem. Any one got any ideas as to what could be causing the problem....??