surely if such a law is (or is not) repealed by a lower court,

AFAIK, long un-repealed laws are not necessarily law. Any new law, that effectively** supercedes an old law, makes the old law null and void. Didn't "Time Immemorial" establish that precedent?
Of course, if parliament now rushes through new laws and doesn't debate the full implications they becomes a lawyers' cash cow.

**You know the old saying "laws are made by lawyers", it was so true in the days when so many barristers could lawyer in the morning and play at being MPs in the afternoon. It is a moot point whether less barristers in parliament means less ambiguous laws or moreso!