Hello Martin,
that's a good setup. These scope trolleys are very convenient. Have a similir one but had to upgrade the wheels to a bigger version (have to roll over uneven ground). I marked 2 places on the ground were to pace the soutern (in your case suppos the northern) support screws. So after one polar align the mount is always correctly oriented.
How did you make the support for the motor? Is that 3D printed? I never connect the belt to the reduction knob. These tend to be very fragile and stepper motors have much torque. (Since you already have a reduction on the belt, and with stepper motors you can reduce the step rate that is probably enough. (or a geared stepper motor)
So now you can't drink beer anymore since you gave the can holder another job. Sensors can get fairly hot, especially the Sony ones. On a warm day in the Sun I notice also ~40°C, and warm here is not what you have in Australia. Would a small ventilator do a better job? You might have covered the vent holes in the cam.
Anyway the pics are good. And so is the location. Now an SSSM and a plugin to control captures and you can take a swim while capturing
Regards,
Paul