My A levels were taken many years ago and are rather mediocre. How do I get over the problem with online applications that will not let me continue beyond the question of A levels?

First I would ask if there were mitigating circumstances to explain why your A level grades were low, as often online forms allow you to proceed by ticking a ‘mitigating circumstances’ box. If there aren’t specific circumstances I would still tick that box so you can get through to the next stage, then explain in the relevant section that your A levels were taken a long time ago. Law firms are aware that people coming from a career change may have different skills on offer in any case and recent academic performance may be a greater reflection of your capabilities. Please note that this wont work for everyone (for example, recent A level takers shouldn’t get around low grades this way). I would also add that making some form of personal contact with individual firms to establish the best way to get over the A level hurdle will help, whether that is at law fairs or via telephone or email.