So, the run of clear nights has not been the success I was hoping it would be.... The system halted at around 12:30/12:40 every time - failing to plate solve seemed to be the main cause of the issue - but I couldn't work out why.
[System comprises MaximDL for guiding, acquisition controlled by CCD Commander which also monitors the weather conditions with my AAG. Taking a break from SGP as CCD Commander has (at this moment) slightly better handling of weather conditions that SGP - I suspect that will change in future, but anyway....]
So, Sunday night, I stayed up and baby-sat the rig - I was doing some playing with other stuff, so not a wasted evening at all - got to look through my new ES68 EPs in my ED72 - which was very nice!!
Anyway, we get to the appointed time when the failure occurs, and I can hear repeated "Slewing to target" alerts from EQMOD as it struggles to get in the right position and plate-solve. I dash in the observatory and realisation dawns on me!!
I was test-imaging M81/M82 and had completely forgotten that as they drop down to the bottom of the orbit around Polaris, they are obscured by some tall-ish trees a short-distance away from us... Of course, they have grown a bit over the year, making the problem even worse!!
No wonder I couldn't get a plate-solve from it!! So, made a cup of tea, did a bit more observing through the 72 for an hour or so, until we had cleared the trees and off we went again!!
What a dunce I am!