Peel the squash, remove the seeds, cut into approx. 1 cm cubes. Slice the onions and garlic. Place everything in a pan of salted water and bring to the boil, cook for approx. 4 mins., drain well, fill the sterilized jars to just below the rim. Halve the chilli lengthwise, remove the seeds, bring to the boil with the peppercorns, vinegar, water and salt, pour the boiling hot liquid over the squash to just below the rim. Seal the jars immediately, allow to cool on a towel.