In answer to your question of course you have a chance if your CV is strong enough regardless of university. It is not surprising that students for the top 5 university are over-represented but that’s because they are generally strong candidates - it has nothing to do with their university. Every single candidate is assessed on merit. Going to a top 5 university does not automatically mean you will be a good commercial lawyer just as going to a lower ranked university doesn’t mean that you won’t. Commercial law firms are geared to make profit and the candidate that has the most chance of being successful in this environment will be selected.