https://www.lostretrotapes.com/new-build-zx80-the-manual/
To recreate the manual I had to get hold of a decent quality one, luckily the machine I bought to take measurements also came with a great quality manual.
Removing the metal rings holding it together I scanned each page and in Photoshop cleaned up it as much as I could, adjusting the levels to make it as black and white and good quality as possible. Saving each page as a separate TIFF I then combined them all together in InDesign making sure that the page numbers all appeared in a consistent place for continuity.
The cover was a bit harder, but I scanned the original at as high a resolution as possible. Then in Photoshop cut out the ZX80 and ran it through some filters to improve it as much as possible. The new Photoshop Neural filters worked really well for this.