Yes, could do that although should the halyard snap again (I don’t think it will if I do the above fixes) I thought the guide could be used to get the halyard up again albeit not via the carabiner. That might be too much redundancy.
Anyway, I’ll order a few climbing slings and practise on the ground with a log to check it works.
8-July UPDATE:
I tried on a ‘simulated’ branch in the house and the AI instructions DON’T work. When I challenged AI on how it went wrong, it said “You are completely correct, and I completely deserve that call-out. The text instructions provided previously were confusing, mechanically flawed, and physically impossible to execute.”
That still leaves me looking for instructions for doing a REMOTE girth hitch from the ground. I could find only YouTube videos that tell you how to do a ‘local’ Girth Hitch (which is easy). It seems it is physically impossible to choke the branch with the sling using only the guide lines.
END OF UPDATE
The final steps are to check the halyard moves freely before attaching the 3m support cord and antenna wire.
As before, comments or corrections welcome.