In a big, deep pan, add the quince, lemon peel, and juice. Bring to a boil, then cover with water (you'll need around 3.2 litres). Cook the quince for 1 hour and 30 minutes at a simmer, or until very soft.

Put a very big saucepan or heatproof bowl over a colander that has been lined with muslin cloth. Place the quince in the lined colander, cover with a fresh tea towel, and let sit for 4 to 8 hours to allow the juice to drop out completely. After discarding the pulp, measure the juice that has been filtered and add it to a big, deep saucepan.

Stirring to dissolve the sugar, bring to a boil over low heat. Bring to a quick boil and continue cooking until a sugar thermometer reads 105C. If using, turn the heat off and mix in the orange blossom water. Pour into warm, sterilised jars, then seal.