pinch chilli flakes (optional)
3 cucumbers (about 1kg/2lb 4oz)
1 tsp dill seeds
1 large onion or 2 small, thinly sliced (approx. 200g/7oz prepared weight)
1 tsp celery seeds
2 tsp yellow mustard seeds
1 tbsp fine sea salt
150g/5½oz granulated sugar
½ tsp ground turmeric
300ml/½ pint cider vinegar