Line your baking tin with parchment paper and set aside for later.
Crush the rich tea biscuits into small crumbs leaving a few bigger pieces for texture.
Melt butter, caster sugar, honey and cocoa powder over a medium heat or in a microwave until melted. Mix the mixture until combined.
Pour the melted butter mixture into a large mixing bowl and add the crushed biscuits and chocolate raisins. Mix together until fully combined.
Pour the tiffin mixture into a lined 9″ tin and press down with the back of a spoon until compressed. My tip is to use a clean spoon to press the tiffin mixture down, otherwise the mixture will stick to the spoon.
Melt the white chocolate, milk chocolate and dark chocolate in different bowls. Blob each chocolate on top of the tiffin mixture in different areas.
With a skewer or toothpick, swirls the chocolate to create a marbled look. Ensure the chocolate evenly coats all areas of the tiffin base.
Place the tiffin in the fridge and leave to cool for 2 hours or until the tiffin has hardened. Once chilled, cut into 16 slices.
2 hours chill time is not added to the overall time.