Hi Ant. Welcome to Mozguide. The Limpopo basin has just had a higher than usual rainy season. Normally the level is low enough at Pafuri to drive through from mid June to December. Your best contact in the area is Dumela Wilderness Safaris located on the banks of the Limpopo 7km from Pafuri in Mozambique.
I have been to Gona a few times via this route. Beware at Sango Zim border post, the policeman at the entrance boom can be very eager to find fault so have papers in order and check how to find your engine number.