Robin - there is no mystery now.
Patrick - thanks for letting me know. It appears that there are many Astrodudes out on the internet. Nice website BTW.
Steve - I have done some more digging and now have the answer to your question. The video was produced by Mitch Arsenault who appears on various forums, twitter and all the usual culprits as @astrodude or @rcfmitch. If you get on Youtube and search for 'rcfmitch', that will lead you to Mitch's videos including some Pixinsight Tutorials. Maybe the video you want is in there? Alternatively if you go to
https://rcfmitch.wixsite.com/altair-support (his web site) and click on the Donate button, then his email address is revealed. So he gave it to you, not me.
Hope this clears up the mystery.
Dave