That book was going to be the manual as SoC commissioned Williamson to write it along with his prototype paying him about £5K I believe in embarrassment when they dropped his design.
Not sure who wrote the manual - maybe the used some early portions of the draft that Williamson wrote?
David Johnson-Davies wrote the Further Applications Programs one and he believed Nick Toop wrote the VDU and Cassette ones.
I wonder how much input Tony Amendt had as he was the NS liaison to SoC (see comment on this entry
https://www.old-computers.com/museum...sp?c=1147&st=1
I cant find the reference but Steve Furbur also said he wired the first prototype somewhere.