Cut the courgettes into slices lengthways, so that they end up as strips. Simmer the garlic in the oil gently for 2 minutes, and then put in the courgettes. Keep them moving about until coated and beginning to colour lightly. Pour in the vinegar and water and cover with foil, or a lid. Simmer for 10 minutes.
Meanwhile, rinse the anchovy fillets if salted, or drain the oil from canned on