No, you don't have to hold for the week. Here with the announcement.
Payment in South African Rands of both the initial capital reduction of 1021 cents a share and the dividend distribution will be made on Monday, 3 September 2007 to shareholders recorded in the register on Friday, 31 August 2007. The last day of trade to qualify for the dividend will be Friday, 24 August 2007 and the shares will trade ex-dividend from Monday, 27 August 2007. Share certificates may not be dematerialised or rematerialised between Monday, 27 August 2007 and Friday, 31 August 2007, both days inclusive.
The last day to qualify is 24 Aug (you hold at the close on this date you get the div). They will pay to share holders registered on 31 August, but note there is no materialization happening between last day to trade and record date. So you can trade the share but with T+5 (five days before actually ownership changes hands after a sale) there is no updating the register.
Bottom line when you buy or sell is not important. As long as yopu hold on LDT (24 Aug in this case), you get the div.