Update,
I ran the 24 hour report a few times using different loggers and different users. They were all coming up with data from the end of Jan 2016 and the beginning of Feb 2016.
I edited the Excel spreadsheet, removed the good data, left in the old data, set the annotation to delete and imported the spreadsheet back into Mango. I then re-ran the reports.
I had to do that a couple of times but it seems to have cleared the old data.
The next few reports did not have the old data.
Problem solved for now.
Cheers
Brian