Diplomatic relations — Immunity — Foreign States Immunities Act 1981 — Entitlement of diplomatic envoy to act on country’s behalf in legal proceedings in another country — Whether acting Attorney-General entitled to represent Government of Lesotho in legal proceedings outside Lesotho — Section 98(1) of the Constitution of Lesotho — Whether waiver of immunity — Whether investigation into customs fraud an activity in exercise of sovereign authority — Whether Court possessing jurisdiction — The law of South Africa