hg rebase or how to move trunk/default changesets to a branch

Scenario:
One wishes to move changesets on trunk (starting with revision A onwards) to a new branch B.

1. Enable the Rebase extension for you / the repository per the RebaseExtension docs
2. If outstanding changes, commit or shelve them!
   (otherwise next step will generate merge request)
3. hg update <A-1>
   (the one before you wish to move to branch B)
4. hg branch B
5. hg status
   confirm output has no actual changes (branch change won't be shown)
6. hg commit -m 'create B'
7. hg branches
   get actual revision for B, we'll call it C
8. hg rebase -s A -d C

That's it.  If insufficiently clear, I can post some screenshots, etc.  Do ask but expect delayed response unless you tweet me!