Thanks, Manuel. Pretty tricky manual hacking, to figure out your approach above!
I’m afraid that, though experienced in other languages, I’m not deep in PHP & setting this website up for non-technical people. I’m also concerned about future WP/plugin upgrades causing the ‘breakage’ to come back.
For those reasons, I am trialling QuickCache instead. It worked out of the box (though another CodeStyle Localication dislikes the fact that it decorated CodeStyle’s screen).
The first cache I’d tried was W3 Total Cache. This worked perfectly out of the box, but it was big & intrusive on the Dashboard left-hand menu.
So I had hoped that Super Cache would be fully packaged/ perfectly self-configuring & sufficient for this website’s needs. 🙁
Thanks for your great response, I’m sure it will be helpful for others installing Super Cache!