I can’t creep over the limit the car has detected. The accelerator does absolutely nothing once that limit is reached. The car will not brake for you though, so even a gentle hill will cause speed to increase. Even then you should be hearing the beeping once you get to 31 in a 30 for example. If you’re not, the system is either not set properly or it is malfunctioning.
One interesting, but in hindsight entirely predictable, malfunction I had the other day was a complete failure to read any signs. The cause was a petal off one of those blossom trees sticking to the windscreen in exactly the right place to blind the camera, so check the windscreen before setting off.