If you do something using a power from a law that gets repealed or amended, it still has effect. This happens even after the law is repealed or amended, as long as it was in effect before the change. You can think of it as if the power was exercised under a different law that replaces the old one.

If a new law replaces the old one, or is similar to it, the thing you did using the power still has effect. This is because the power can still be used under the new law. The new law may be modified, but the thing you did still has effect as if it was done under the new law, as you can see in the related legislation.