The email that says 'Your application is currently under review and we will be in touch after the deadline to advise on the outcome of your application' is one that you will receive after completing the test to essentially confirm that they've received your test.
If you pass the benchmark, you will then receive another email saying 'Thank you for submitting your application to
Herbert Smith Freehills and completing our online test. I can confirm that you have reached the benchmark on our online test and your application is now under review.'
Hope that helps