I have concluded that the problem I was experiencing was due to the relatively low mileage (<20 miles/day) on my regular commute, and the depletion of the battery as a result of 5-10 auto stop/starts per day. The problem only appeared some 6 weeks after taking possession from the dealer. It then disappeared after an appointment with the dealer to look into the problem. They found nothing wrong but apparently charged the battery during the visit, which would explain why the issue appeared to go away for a while before re-appearing in early December.
I have now turned off the auto-stop feature and don't think that I shall have any use for it as long as my daily mileage is as low as it currently is. I must say that I agree with the posts made elsewhere about the strain imposed on the battery by this feature.