In a large bowl, combine the zucchini, corn, eggs, spring onions, parsley and cheese. Whisk well with a fork. Add flour and seasonings to the mixture and mix well.
Heat a large frying pan over medium heat. Pour ¼ cup measures of batter into the pan, adding some of the oil each time, and cook for several minutes until golden. Turn fritters and cook a further 3-4 minutes until golden and cooked through. Keep fritters warm whilst the remainder of mixture is cooked.
Serve fritters with sour cream and sweet chilli sauce.