Can't delete backup - says corrupt

I have attached a screenshot of my backup directory (ie what is physically on the backup media). It shows 2 incremental backups done on the 22nd Sept at 8.06 and 8.12. I think I may have started a backup, cancelled it and then restarted. When I go into the browse for backups screen in order to delete a backup version, only one backup is shown on that date, time stamped 8.03. If I try to delete that version, I get a message that it can't be opened because it is corrupt. I planned to delete that version, and then manually delete the other versions which don't appear to have registered as backups, probably because the other one was corrupt.

Is there a way to remove the rogue backup dated 8.03 from the backup register? And the versions timed at 8.06 and 8.12 which don't appear to have registered - I would like to delete those also to regain the disc space. However if I manually delete those from the disc, will ATI recognise the deletion and show there is more disc space?

Thanks