R on the application of Kadri v Birmingham CC and Secretary of State for the Home Department; R on the application of MWA (by his solicitor and litigation friend Kamaljit Sandhu) v Birmingham CC; Birmingham CC v R on the application of JS (Afghanistan) (by his litigation friend the Refugee Council) & Anr; Birmingham CC v R on the application of YK (Afghanistan) (by his litigation friend Kamaljit Sandhu)