It will be good if its just the battery (its a wear an tear degradable item so don't worry. A pain yes. Major, no).Savs, you may be right cos just had a call from the garage, they tried to charge the battery overnight but it wouldn't hold charge, they checked the battery and it's the wrong type AND it's a Mercedes battery. Diagnostics threw up TWENTY TWO fault codes. They've ordered a new battery which should arrive late afternoon then take it from there. Hey ho!
I've had a battery go on me once. No warning and it was when i finished work (had to bump start to get home, Passat 1.8T).
What i learnt was modern batteries give no warning. Only weird warnings like a separate unrelated system going down.
On the plus side, if you know someone with VCDS you can turn on a battery monitor that can be displayed via MMI (same as electronically checking oil). That being said, a new battery should last a long time. Fingers crossed this solves the issue and you're back up and running!