Remove the right-hand cooking grill and replace with a cast-iron half hotplate. Preheat the barbecue with burners on high for 10 min.
Place the flour, milk, and eggs in a large bowl and whisk until combined. Stir in the corn, zucchini, and cheese. Season with salt and pepper and mix well.
Once the barbecue is preheated, turn the burners to medium.
Oil the hotplate, and then spoon on heaped tablespoons of the mixture. Make sure a gap is left between each fritter so they do not touch. Half the mixture will make 12 fritters that fit on the hotplate all at once.
Cook the fritters for 2 minutes on each side or until they have puffed up and are golden. Remove from the hotplate when they are done and cook the next batch. Serve the fritters with smoked salmon and poached eggs, topped with sour cream, rocket, and red onion.