Thanks for replying, Guust.
I have installed Libre Office (had thought Open Office was OK, but good to know the latest recommendation) and added one event via the front-end, exported that then added new data to that sheet in order to upload.
The first try worked well apart from the date being read YY-MM-DD instead of DD-MM-YY, so checked the formatting of that column, and… still insisting on reversing the data for the date.
So going to offer the date up in that order… And that worked. Worth noting for future reference, though.
The times are uploading just fine now, too.
Thank you.