Combine flour, butter and sugar. Mix well till a dough is formed. Press into the bottom of a baking tin.
Bake in a preheated 180 C / Gas 4 oven for 20 to 25 minutes, or until lightly golden. Set aside to cool.
For the caramel:
Add the butter, sugar, golden syrup and condensed milk to a non stick pan. Bring to the boil, stirring constantly. Continue to stir while boiling for 5 minutes. Remove from heat when the caramel is a light brown colour and thick consistency.
Pour the caramel over your shortbread and put in fridge for 30 minutes to set.
Once set, melt the chocolate in a double boiler or in short 30 second intervals in the microwave. Pour melted chocolate over the caramel. Place back in the fridge till set, about an hour.