International organizations — Administrative tribunal — Form of decisions — Loss of pension entitlements — Whether settlement of 20 November 2002 binding on International Energy Agency (“IEA”) — Validity of Governing Board decision of 3 April 2003 — Terms of appointment — Relevance of principle of good faith — Legal obligations — Whether IEA acting improperly — Whether moral injury to applicant — Whether Tribunal having jurisdiction to determine applicant’s principal and subsidiary claims