One I'm using at the moment is one given by one of our members.
1KG of sugar 250 ml of water.
Dissolve sugar in a saucepan with the water over a light gas flame.
Stir continuously.
Bring to the boil, (it will go clear) for one minute
Take off the gas, and place the solution, still in the pan, in a bowl of cold water (I use the kitchen sink)
Stir until it starts to set (it will go silver grey)
Pour into an empty ice cream container, leave to set.
Put on the lid, and cut a hole in it about 25 mil diameter
Line up the hole with the hole in the crown board and leave them to it.
Carte D'or containers are good, you can see how much is left.