Grate the courgette into a sieve, add the salt and rest for 30 minutes over a bowl. Squeeze out the excess moisture using the base of a spoon against the sieve.
Put the courgette into a large mixing bowl.
Drain the chickpeas and add to the courgette. Add the spices, garlic, onion, herbs and chickpea flour. Season with salt & pepper (you can add a pinch of cayenne if you like). Combine well.
Put half of the mixture into a food processor and blend, scraping down the sides of the food processor as necessary. When you get a coarse mixture, resembling couscous, transfer it into a bowl. Repeat the processing with the remaining mixture.
Combine well the two blends and cover the bowl with clingfilm, then chill for 2 hours (or place in the freezer for 20 minutes).
Add the bicarb to the falafel mixture and combine well, then form small patties or balls. Put them on a plate.
Heat some grapeseed oil in a small, deep pan to the depth of 3 cm. Fry 4-5 falafels at a time for about 2-3 minutes per side, or until golden brown. Add more oil to the pan as necessary.
Transfer the falafels onto a plate, lined with paper kitchen towels.