Information from Alex Blok at the Picosm website.
Also contains some limited information on the CPC/C64/BBC versions:
https://docs.picosm.com/pcwstoppress/ (https://docs.picosm.com/pcwstoppress/)
Full review of the PCW Stop Press in 8000 Plus magazine (pages 18 - 22) is available from here:
https://ia800302.us.archive.org/18/items/8000-plus-magazine-17/8000_Plus_17_300dpi.pdf (https://ia800302.us.archive.org/18/items/8000-plus-magazine-17/8000_Plus_17_300dpi.pdf)