“33. First there can be no doubt but that the normal position in public law where a decision is quashed is that the decision-maker is free to reconsider the decision in light of the material circumstances then prevailing at the time of the fresh decision: see, for example, R v. Secretary of State for the Home Department, ex parte Zeqiri [2002] Imm AR 296 at paragraphs 42 and 43 of Lord Hoffmann’s speech”