@ nijel
Ops ... My profile in C:? It's sure a refuse of Design Time progamming. I'll fix it
A question? Your csv POI which Data format is in use?
The bugs you report are tipically due to a Coord Swap (Lat e Lon swapped). The Program start with a default Parsing of LON, LAT, DESCR (as Garmin csv docet).
If yours are LAT, LON formatted you have to swap Coord Parsing in Main window, BEFORE applying Filtering.
You can verify that in View POI window ...

I empty Destination Folder to be sure that exported Data are those, and only those, you want (Settings may have changed meanwhile ...)