Just after the help provided in this topic I did the job with Calibre and regex.
A good training that is time consuming.
To compare, I did the job again with the Sigil automated plugin.
I had to correct my anchors by regex again.
I spent less than half an hour to discover and to link 115 notes and 115 rearnotes.
Once the syntax is correct the creation of the links is faster than it takes to blink.
Thanks to all helpers.
sigil plugin here:
https://www.mobileread.com/forums/sh...d.php?t=288193