“If when the Tribunal reads the Special Adjudicator’s decision there is an obvious point of Convention law favourable to the asylum-seeker which does not appear in the decision, it should grant leave to appeal. If it does not do so, there will be a danger that this country will be in breach of its obligations under the Convention. When we refer to an obvious point we mean a point which has a strong prospect of success if it is argued. Nothing less will do.”