Hi Valentin,
Thanks for the speedy reply.
Using internal guiding with 360mm f/l refractor has worked well for months. Since switching to the 750 f/l reflector I'm having these problems.

I did try PHD2 last night. I ran the Guide Assistant which on one run told me:
Try setting RA mi-move to 0.11
Try setting DEC min-move to 0.18
Polar Align > 10 arc min
Measuring Backlash: Mount never established consistent south moves - test failed

So I did make the min-move changes back in EKOS guider, as you saw.

I rebalanced the mount and retried:
PHD2 is not able to make sufficient corrections in RA.
Check for cable snags, try redoing calibration and check for problems with mount mechanics
Could not clear North Backlash - test failed

I have the debug files for that which I'll attach.