In completely unrelated Excel news....
The BBC has confirmed the missing Covid-19 test data was caused by the ill-thought-out use of Microsoft's Excel software. Furthermore, Public Health England (PHE) was to blame, rather than a third-party contractor.
The issue was caused by the way the agency brought together logs produced by the commercial firms paid to carry out swab tests for the virus.
They filed their results in the form of text-based lists, without issue.
PHE had set up an automatic process to pull this data together into Excel templates so that it could then be uploaded to a central system and made available to the NHS Test and Trace team as well as other government computer dashboards.
The problem is that the PHE developers picked an old file format to do this - known as XLS.
As a consequence, each template could handle only about 65,000 rows of data rather than the one million-plus rows that Excel is actually capable of.
And since each test result created several rows of data, in practice it meant that each template was limited to about 1,400 cases. When that total was reached, further cases were simply left off.
Until last week, there were not enough test results being generated by private labs for this to have been a problem - PHE is confident that test results were not previously missed because of this issue.
And in its defence, the agency would note that it caught most of the cases within a day or two of the records slipping through its net.
To handle the problem, PHE is now breaking down the data into smaller batches to create a larger number of Excel templates in order to make sure none hit their cap.