Mr Lobster

Thanks for the reply. I have seen those options and eventually I had to use them, and they can be used as a workround to my issue. It would still be helpful to export channels as layers though.

I have noticed a colour shift when I am converting RGB to Fogra39 CMYK for print. This is of course natural as there is always loss of colour info in any cmyk colour space conversion, fact of life. In order to compensate for this I want to manually manipulate the CMYK channels and modify the colour percentages. In PS I would have just copied the channel contents to layer, made the adjustment and replaced the original. How can I do this in Affinity Photo, cannot see how to achieve this?