After updating to KMyMoney to version 4.7.2, every time I save my data I receive a consistency check report commenting on the date of certain transactions. These are identified with a label of the form "T00000000000000000001".

How can I relate this ID to a dated transaction in my database?

You should be able to search for that transaction, just enter the transaction id in the search filter

Sadly KMyMoney search filter can't find any of the Transaction IDs it is complaining about - not in any of my accounts.

How is that then? KMyMOney finds a transaction it doesn't like for some reason, but cannot find that same transaction when asked to search for it.........

How else can I find this offending transaction?

Sadly, the only way is to unzip the .kmy file and open the resulting .xml file with a text editor, then search for the transaction id

One has to use Edit/Find transaction and enter the exact transaction id in the text search field. Using the filter in the ledger does not work. This might not be available in older versions of the application.