Thank you all for your input.
I agree with Glen - stars look soft so I checked what might have caused that - it was a speedy processing with Local Histogram Equalisation with no star mask.
So here is unadulterated version with Historgam stretch only.
https://www.astrobin.com/full/351798/B/?nc=user
I can sleep peacefully again. Thank you Glen.
Either way - I shall collect flats for Ha and move on to OIII.