This time of year, rivers are quite quiet as far as fly goes. A few kob, bream etc but the kings, skipjack etc are usually gone. Upper reaches may hold a few kings still and mouth area a few shad.
Went one year in june/july bliksem cold! Umzimvubu River is the place to be. If the water is clean park next to the river on the cremorne side,by the big tree.