I noticed that the map I used to show multiple locations on was still showing posts that I had moved to drafts so I removed the location information and reset the maps on those posts to see if they would be removed from the map. Still there.
Then I went to the list of saved locations and un-checked the locations I no longer wanted to show up and saved it. It took a long time to save settings and once that happened the map no longer displayed at all, just a big blank space where it had been, showing it was allocating the space, but no longer showing the map.
here's the template tag I used: <?php echo geopress_map(750, 750, 50)?>
I've removed the map completely from the page to avoid confusion now. I note that the maps in individual posts still work.
It looks like the locations table has gotten corrupted, as there are now a number of odd entries there.