All,
So I have allowed ArcPro to update to 3.1.0. It decided my cloned python environment was broken so I had to delete it and clone another, that seemed to go all OK. I then installed spyder into the new environment, that was more problematic but I solved it and can confirm spyder opens OK and is aware of arcpy, so that seems to all be working OK.
But the upgrade lost its link to the default script editor, so I reset that under the GeoProcessing Options as shown below:
But when I right click and choose edit on my toolbox that I am developing python scripts in it opens the script up in the Windows notepad and not spyder.
It seems to unpack the tool script into a temporary folder location, for example C:\Users\hornb\AppData\Local\Temp\ArcGISProTemp14556
I'm desperate for advice as I am unable to develop my code, I need to open it in spyder, not windows notepad!