If you didn't set up a way to keep the tunnel config on your server persistent, then yes you need to re-run the commands on your server. Otherwise the tunnel doesn't get removed on our side automatically.
The above suggests that the tunnel *will* be removed on the HE side if it *is* made persistent on my side. (?)
I was concerned that by re-creating the tunnel at my end, I would be setting up a second tunnel at HE.
Anyway, I went through the steps again, and found that the same tunnel was now working for me. No duplication problem.
I can reach out via ipv6 to the ipv6-enabled world, sort of - ping6, etc., work; some ipv6 web sites respond via certain browsers and not others.
I still did not get my ipv6 web server working, and begin to grasp that I may need the cooperation of the DNS meisters at my worksite, to make my web site visible via IPv6. (I am not running my own DNS server)
I'll get on with this after the break.
Thanks to all for your time & ideas.