A Mini Marcos at the 1968 South-African GP - UPDATED

Like so many Formula 1 events, the 1968 South-African Grand Prix of South-Africa, which took place at the Kyalami racing track, is pretty much covered. You won't find it difficult to find pictures of the event. But they all focus on the Lotuses, Brabhams, Ferraris, MacLarens and what else have you.

Reader Alexander Trimmel sent me a picture, taken during the event and showing perhaps a bit of a surprise. He wrote: "Hello Jeroen, I do not know if you have it... For me, this is a very interesting shot, taken on the 1st January 1968, South African Grand Prix: In the foreground, you see Jack Pretorius in his Brabham BT11 4-cylinder Coventry Climax FPF. But have a look at the car in the background...

Hey! That's a Mini Marcos. In blue and yellow, like mine (it's not that though) and with notable pattern in the striping. Anyone who knows more about it? 

UPDATE 2 September 2020: It's Peter Kat in the factory-built ex-Le Mans racer, as confirmed by a copy of the race program sent in by reader Surfblue63 and mentioning the car as having 1143cc. Now we know for sure the green 1967 Le Mans car was repainted when in Africa. More (black and white) pictures of it can be found here and here. 

Yes, there's a Brabham-Climax Formula 1 car in this picture. But look behind it!

Picture via Alexander Trimmel