The Court may reference this in obiter, but cannot expressly overrule it or set it aside because legislation prevails over case law

Nothing. The doctrines of parliamentary sovereignty states that once Parliament has legislated, no court can override or set aside the legislation

The High Court has the power to set aside legislation if it finds that it is unconstitutional

The High Court needs to refer the matter to the Privy Council in the UK who have the ability to set aside the legislation