This name doesn't match `base::user`:
```
Info: /Stage[main]/Base::Mounts/Ext4mount[/srv/backup-data]/Mount[mount-/srv/backup-data]: Scheduling refresh of Mount[mount-/srv/backup-data]
Error: /Stage[main]/Base::Mounts/File[/srv/backup-data]: Could not evaluate: Could not find user govuk-backup
Notice: /Group[govuk_backup]/ensure: created
Notice: /User[govuk_backup]/ensure: created
```