After a few cold mornings last week with most of the electrics switched on, I noticed on the MMI battery meter it had dropped to 60%, having never really been lower than 90% beforehand. Ran around with the car for a few days, with everything switched off, just to monitor the battery, and it never went back over 60%. It was the original (2009) battery, so I assumed it was on it's way out, and I didn't fancy coming out to the car in the middle of winter for it not to start. I priced up a few batteries, but aftermarket ones are difficult to code in with VCDS as they don't have a BEM code sticker to update the battery regulator/monitor. My old original battery was a Varta 110a/h, so I went to TPS to buy a genuine replacement. The old battery number 8K0 915 105F has been superseded by part number 000915 105DL and costs £193.94 RRP. With my discount it came to £139.64 which is perfectly acceptable for a OEM battery.(these battery's are huge!) All fitted and coded in no problems, and MMI battery meter is back up to 100%. All ready for winter now!