ALEXANDER WINNING INVESTORS are celebrating the suspension of one of the main party rivals of South African President Cyril Ramaphosa as a sign that he is finally tightening his grip on the governing African National Congress (ANC). But they say Ramaphosa must move far more quickly on reforms before they can turn bullish on the growth prospects of Africa's most industrialised economy. Ramaphosa has slowly consolidated control over the divided ANC after narrowly winning a leadership contest in December 2017 that also saw enemies elected to powerful party posts. He only felt confident enough last week to move against Secretary-General…