Hey Malcom, White Dwarf, Thank you for the answers. The Andromeda test was inside the house to see whether the mount was tracking. It seemed it tracked 🙂 Last night I performed another test on M42 and NGC2264. I got good polar alignment. ( I checked it again after I returned home the mount after around 3 hours of shooting and Polaris was on the spot where it should be at that time. So that is all ok. I balanced the mount for the home position etc. All levelled. I did a two star alignment. Sirius and Mirfak. When mount slew to Sirius, Sirius was a bit out of the middle. I centred it. Then the mount slew to Mirfak. Mirfak was spot on in the middle of the eyepiece. I selected M42 as the first test. (Olympus EM1 Mark II and WO Redcat 51) - 60s are ok. 90s gets blurry images - 120 / 150 / 180 not worth considering (I get 3min with my Skywatcher star adventurer) - I moved the to the Christmas Tree cluster. From the 40 images I took at 120s - Only 40% of the images are usable. There was no wind.
I have no idea why I can't get longer exposures on this mount.
Tomorrow it seems to be clear again. I will do the bright star test to see whether it drifts out of the centre.