OK I emailed support@ and they sent me the order email almost immediately, so that was nice.
Unfortunately this didn't really help as the dl site (
http://www.getpenumbra.com) seems to have gone away.
But anyway it turns out the 1.1 upgrade was available on this site all along --
http://support.frictionalgames.com/entry/65/
But despite the filename, it actually upgrades to 1.0.3013 (which is not mentioned in the changelog).
After upgrading and removing the PenumbraOverture/lib/libvorbis* files again, it has exactly the same graphical problem.