I've had countless battery warnings in my 2016 Octavia SEL 1.4 TSI.  The battery is EFB.  The dealer has tested it three times and says it's fine, so won't replace it.   So, I'm considering buying a replacement, if only to avoid the constant hassle.  All the online vendors advise that this model should have an AGM, yet I've read these two types of battery should not be changed for the other (here).  Is this correct, or can I move seamlessly from EFB to AGM, assuming the car is re-progr