sentences:  However, in August 1984, South African foreign minister Pik Botha decided not to allow the Coventry Four to return to stand trial, forfeiting £200,000 bail money put up by the South African embassy in London.In April 1984, Thatcher sent senior British diplomat, Sir John Leahy, to negotiate the release of 16 Britons who had been taken hostage by the Angolan rebel leader, Jonas Savimbi.At the time, Savimbi's UNITA guerrilla movement was financed and supported militarily by the apartheid regime of South Africa.