I have just heard of another Exide AGM 12-31 failing completely in use, this time on a motorway near Hamburg. It seems that there is certainly a problem with these batteries in M3W's. At least two of them have killed the rectifier at the same time as failing. If you have one of these fitted it would be worth considering a change, particularly if it has been fitted for about two years or less as these failures have all been in that range.