Thought it might be useful to add my own update here - I was/am using a very old version of kstars/ekos (3.0.0) which I can make work with the iPolar for PAA happily. Recently I have been trying to upgrade to 3.5.2 and cannot make the iPolar work with it at all (the image it takes is deemed unsolvable). I know it's Ekos as I made sure every other driver was the same on the system (indi, kernel etc) but as yet don't know at what point between 3.0.0 and 3.5.2 it stops working.