Preheat your oven to 180℃ (or 160℃ for fan ovens) and line an 8x8 tin with baking paper.
Add the butter, sugar, peanut butter and golden syrup to a large saucepan. Place it over low heat and stir gently until the butter has melted and the sugar has dissolved.
Remove the pan from the heat and stir in the oats and the pumpkin seeds. Mix well so there are no dry patches or sticky spots left in the pan. Transfer the mixture to your lined tin and press it down firmly.
Sprinkle the chocolate chips over the top and gently press on them to help them stick.
Bake for around 15 minutes, until golden around the edges.
Leave to cool in the tin for about 2-3 hours.
Once set, remove the flapjack from the tin, cut it into slices and enjoy!