A further update from the land of Abbott, having decided to call them this morning because the sensor is reading >1 mmol/l out again this morning in s a slow moving scenario.
The chap on the end of the phone was very helpful, and gave me some useful information. In terms of what Abbott considers to be poor accuracy, it is a scan variance from the average of a group of blood test readings at a particular level that is greater than 15%. They agreed to replace the sensor due to the high variance at the low blood sugar level I saw this morning and not because of the scan being 1.2 higher than the blood glucose reading when it was 7.2!
I also asked about issues and the guy on the phone mentioned that the group he belongs to didn't have data relating to number of problems. His view was that, given the number of sensors they have dispatched, the difference between good ones and bad ones was that there was an order of magnitude difference, if not two. So the number of bad sensors is somewhere between 1 in 10 and 1 in 100. His view as that there were no widespread issues and as far as Abbott are concerned, they haven't had a faulty batch.