Diplomatic relations — Diplomatic immunity — Diplomatic agents — Family of diplomatic agent — Extent of immunity — Child custody dispute between diplomatic agent and spouse — Jurisdiction of courts of receiving State — Waiver — Vienna Convention on Diplomatic Relations, 1961, Articles 1, 31, 32 and 37 — Relevance of human rights agreements — European Convention for the Protection of Human Rights and Fundamental Freedoms, 1950 — United Nations Convention on the Rights of the Child, 1989 — The law of England