I am pleased to say that my routine for encryption with Nano using CLI is now working.
I have attached a file with the method I am using to test that this works.
I have to say thank you to Benno Schulenberg for supplying the patch to 2.9.2 and for his guidance in applying it, also for other guidance in this process.
Also thank you to Jalus Bilieyich for his guidance and spotting that I needed ncurses to make the installation of 2.9.2 work.