JOHANNESBURG – The South African Rugby Union have written to their New Zealand counterparts to apologise for the disruption of the Haka before a Test between the countries last Saturday.New Zealand were performing the Haka, a traditional pre-match routine involving vigorous movement, stamping of feet and rhythmic shouting, when several mix-ups occurred at Ellis Park in Johannesburg.”(The mix-ups) occurred as a result of timekeeping challenges and simple human error,” SA Rugby chief executive Rian Oberholzer said in a statement.The closing moments of the Haka clashed with music, fireworks…