Comment 1 for bug 1549285

See my comment #5 about a possible CLI solution on the bug report you linked to.

As for an actual way of triggering a verification through the GUI, I'm not sure it is worth it since it adds clutter in the interface, a verification is run after each backup and a more complete one every two months, and it could make an average user think the backup solution is unreliable and the backups it makes need regular checking.