Solved 🙂
… and for those following along at home …
I now now have OpenSprinklerPi running thanks to Ray’s suggestion, except than rather using ‘AI’, I resorted to ‘HI” (human intelligence).
I made a search using the error code and a number of people had similar issues with different software, but many answers pointed to DNS issues, so, that got me thinking. Perhaps my ‘pi’ cannot see the internet even though it can update/upgrade via ssh etc.
I launched a browser and immediately saw the ‘pi’ could not make web searches so I thought I had narrowed down the problem, so, how to fix the DNS?
During the installation and setup, I had not configured DNS – oops – so I did that here using the default Cloudflare 1.1.1.1 for the ‘DNS servers’ and the ‘Search domains’. I’m not sure if I should be the same settings for both, but it works so, for me, that’s what matters.
The installation ran smoothly, and there we are 🙂
Perhaps my solution might help some else having the same problem in the future 🙂
ps: I’m not sure how to mark this as ‘SOLVED”