Hi Gamkaboer,
SAFISH lives in Knysna and is a great source of info for that area. Search his posts or contact him. We go there atleast once a year, I have a boat there. The Lagoon is riddled with boats, big, fast machines. Make a lot of noise. The fish normally spend time away from all the noise, so fishing tends to decline at this time. The trick is your timing must be right, very early in the morning and late evening, when the lagoon is quiet. If you don't have a boat, then park and walk to the train bridge and you should get Leerie (Leervis; Garrick) in and around there. Please release them as they are not great eating fish and they are such a pleasure to fight, they fight clean and honest. Your best bet for good solid reliable info is SAFISH - get hold of him and read his posts. He knows the area far better than me.
Regards