Pour 125ml (4 ½ fl.oz) hot water into a heatproof jug and stir in the Gelatine until it dissolves. Set aside.
Put the strawberries in a blender or food processor along with the icing sugar and whiz for a few seconds until smooth.
Measure out 125g (4 ½ oz) of the strawberry purée into a bowl and stir in one third of the liquid Gelatine. Divide between 4 x 125ml (4 ½ fl.oz) cylindrical moulds and chill until firm. Keep the jug of remaining liquid Gelatine standing in a bowl of hot water to prevent it from setting.
Once the first layer is firm, spoon 30ml (2 tbsp) of the remaining strawberry puree into a small bowl and put to one side. Mix the remaining strawberry puree with 75g yogurt and half the remaining gelatine. Divide between the 4 moulds and chill until firm.
Once the second layer has set, mix the reserved strawberry puree with the remaining yogurt, the Vanilla Extract and the remaining gelatine. Divide between the 4 moulds then push 4 wooden lolly pop sticks a little way into the middle of each jelly. Chill for at least 2 hours until completely set.
To serve, dip each mould in very hot water for a few seconds to loosen and then carefully tip or pull out the Jelly Pops. Serve immediately with extra strawberries.