1. Preheat the oven to 150°. Line a 2Lb loaf tin with parchment paper.
2. In a large bowl, whisk together the flour, caster sugar, eggs, yogourt, vanilla and lemon zest, until mixed thoroughly.
3. Add the self-raising flour and whisk gently to combine. Fold in the blueberries. Bake @ 150 for 45 mins Cool 10 minutes in the tin, then remove the loaf from the tin and cool completely on a wire rack.
4. To make the glaze, sieve the icing sugar then, using a fork or a whisk, stir in the lemon juice one teaspoon at a time, checking for a thick pourable and opaque glaze.
5. If the mixture is too runny, add more sifted icing sugar. If the mixture is too stodgy and thick, add more lemon juice.
6. When you have the right consistency, pour the glaze over the loaf. Let the glaze dry before slicing (this takes about 30 minutes).
