Last few weeks I've been coming back to my car to find the radio turned itself on when the cars been left alone. Sometimes it could be 10 mins after I've left the car, other times it can be days apart. Normally I'm in the car once a day so its a pain, but not so much of an issue. Being Xmas, it hasn't been used in a few days. Yesterday te battery was dead. Jumped it and the battery seems to have charged and is running OK.
I've read that sometimes the CD sensor starts to play up, and leaving a CD in solves the problem, but hasn't made a difference for me. Last week it had a CD in and refused to play or eject it, but worked fine the next day.
Local VW dealer wants £45 to diagnose the radio, and if its faulty, whatever that costs on top. Can get the Radio for £90 on the internet.