Preheat the oven to 180C (160Cfan) gas 4. Grease and line a shallow 20cm square tin with parchment or greaseproof paper.
Put the butter or spread, Tate & Lyle sugar and Lyles Golden Syrup into a medium pan, heat gently until melted. Remove from the heat. Stir in the oats and cinnamon.
Grate the apples, (with skin on) into the mixture, add the sunflower seeds and stir together. Turn into the tin, level and press the mixture evenly and firmly with the back of a spoon.
Bake for 35-40 minutes, or until golden.
Remove from the oven and cool for 10 minutes then cut into 12-16 pieces whilst still warm.
To make the decoration, quarter the apple, remove the core and slice thinly. Put the golden syrup into a small frying pan, add the apple slices and poach in the syrup over a medium heat for 3-4 minutes. Cool the flapjack completely before turning out onto a board and cutting again with a sharp knife. Decorate the pieces with syrup soaked apple slices.
Tip: these flapjacks are best eaten within 2 days of making also if preferred add chopped hazelnuts instead of sunflower seeds