Do it in the Staging or User Acceptance Testing environment.

This is the right answer! You want a staging/acceptance/mirror environment that's the same as production, right? So make it with nightly restores of the production backups. You get a crisp, fresh staging environment, and regular validation of your backups too. Just remember to run full production monitoring against your staging environment too.

A friend of mine has his staging databases restored every morning (and anonymised) from the previous day's production backup.

Restore it elsewhere.