When should judges make and unmake law? One simplistic and absolute view is that this is something that judges should never do, and that all lawmaking and unmaking should just be left to parliament. But this view indicates ignorance about our common law system, where laws as varied as the crime of murder and the civil laws of contract and negligence all have no ultimate basis in statute. They are judge-made laws.
A better view is that parliament is one source of law among others, but that it is “supreme” in that it can overrule other rule-makers. The judges may (to use the usual euphemism) “develop” the law, but parliament can and sometimes does step in to stop this. There are also specific and politically sensitive areas where the judges are inhibited from developing the law by reason of deference to parliament. And, since Brexit, no court can strike down primary legislation on any basis.