Complex sentence: The Irish Free State never formally adopted the Statute of Westminster, its Executive Council taking the view that the Anglo-Irish Treaty of 1921 had already ended Westminster's right to legislate for the Free State.
Split into simpler sentences: The Irish Free State never formally adopted the Statute of Westminster. The Free State Executive Council (government) disagreed, taking the view that the Anglo-Irish Treaty of 1921 had already had the same effect of ending Westminster's right to legislate for the Free State.