Leave the diced pulp in a bowl in the refrigerator overnight with the sugar. DANGER! Draws plenty of water, do not choose a bowl that is too small!
The following day, put the melon and its juice in a high saucepan, add the lemon juice and roughly puree with a magic wand. Cook together for about 25 minutes. Strain the mixture through a sieve, collect the syrup in a bowl. Then filter this one more time through a large hair sieve. Bring to the boil again and fill into prepared bottles while still hot, close immediately.
Tastes delicious with vanilla ice cream, over pancakes or pudding etc. or topped up with mineral water for soda.