Preheat your oven to Gas 180°C/350°F/Mark 4/ and line the base of a 20 cm (8-inch), square tin with greaseproof paper or baking parchment.
Place the dates in a heatproof bowl and pour on the boiling water. Leave to stand and soften for 15 to 20 minutes.
Once soft add in the vanilla extract and beat to a smooth puree, using a fork or puree in a food processor.
Gently melt the butter in a saucepan, or in a bowl in a microwave.
Mix in the oats, light brown sugar, sunflower seeds, cinnamon and orange juice to the melted butter.
Stir until everything is well combined.
Spoon half of the oat mixture into the tin, pressing it down well with the back of a spoon.
Spread the date puree over the base and crumble the remaining oat mixture over the top.
Bake for 25-30 minutes or until the surface is golden.
Allow the slices to cool fully in the tin before cutting into 15 bars.
Store in an airtight container up to 5 days.