Coarsely grate the courgettes. Put them in a sieve with a pinch of salt and squeeze together a few times to get rid of some water. Leave in the sieve to drain while you prepare the rest of the ingredients.
Pull the leaves and silks off the sweetcorn cobs. Stand the cobs upright on your board and run a knife down them to slice off the kernels. Tip the kernels into a large bowl. Peel and finely slice the red onion. Peel and crush or finely grate 1 garlic clove. Stir the onion and garlic into the sweetcorn, and crumble in half the pack of feta.
Give the courgettes a final good squeeze to get rid of as much water as possible, and tumble them into the sweetcorn bowl. Measure out 75g of the flour and add it to the bowl. Break in the eggs. Sprinkle in a little salt and pepper and stir well to combine. Set aside.
Drain the black beans and give them a good rinse with cold water. Shake dry and tip into a large bowl. Dice the tomatoes. Trim half of the cucumber and dice it. Peel and crush or finely grate the remaining garlic clove. Halve the chilli, flicking out the seeds and membrane for less heat, and finely chop it. Stir everything into the beans.
Grate the lime zest into the bean salad and squeeze in the juice. Finely chop the coriander and sprinkle on top. Add a little salt and pepper along with 1 tbsp oil and give everything one last mix. Set aside to mellow while you fry the fritters.
Pour ½ tbsp oil into a large frying pan and bring to a medium heat. Add 4 heaped tbsp of the batter to the pan to make 4 fritters. Fry for 3-4 mins on each side till golden brown. Transfer to a warm plate and cover with foil. Add another ½ tbsp oil and 4 more tbsp batter. This should use up all the batter.
Transfer the fritters to serving plates and serve with the bean salad and generous spoonfuls of yogurt on the side.