Preheat oven to 150˚C and prepare a 9’’ loose base non stick tin. Mix together the digestive biscuits, sugar, butter and cinnamon. Press into the bottom of the prepared tin and layer it evenly. Refrigerate for 30 minutes. In a blender combine 3/4 of the strawberries and corn starch and process until smooth. Pour into a saucepan and slowly bring to the boil, Stir for a couple of minutes. Cover and refrigerate the strawberry sauce until ready to use.