Rub the butter into the flour then stir through the sugar. Knead the dough (it'll be hard at first) until it comes together, then press into a large lined deep sided baking tray. Smooth with a spoon and bake for around 30 - to 40 minutes until biscuity and golden all over.
Meanwhile, heat the butter, condensed milk and golden syrup in a saucepan, stirring all the time (it can tend to catch). It'll start to thicken up - at this stage take it off the heat. Pour over the biscuit base and leave to set somewhere cold, like a fridge.
Whip together all the ingredients for the cheesecake. If it looks like the mix is a bit sloppy, add more cream cheese or icing sugar to thicken it up. Pour over the set caramel and leave to set again - this may take a few hours.
Heat the cream to just below boiling and pour over the chocolate. Stir thoroughly to make a smooth ganache and pour over the set cheesecake.