Registration of customary marriages under the Transkei Marriage Act : Wormald NO and Ohers v Kambule [2004] 3 All SA 392 (E), Wormald NO and Others v Kambule 2006 (3) SA 562 (SCA), and Kambule v The Master of the High Court and Others [2007] 4 All SA 898 (E)