Right, did some testing again today; and yet another failure to launch
Switched to a 100mm lens and started the PA process. Ekos solved the first image, and the following two after asking me to rotate the mount. And then it just hung there on solving WCS (or something like that) before crashing. So close yet so far.
Rebooted the Pi, and could not get Ekos to solve even one image over the next two hours or so. Even tried with another cpoy of kstars / ekos on another USB drive.