I found this recipe on the Taylor & Colledge website and want to convert it to US measurements and temps - If you can not find the Vanilla or lavender extract pastes you can get them at the web site Taylor&Colledge.com
Beat sugar, butter, vanilla bean paste, and lavender extract paste together in a mixer on medium speed until well-blended (about 5 minutes). Beat in the egg and egg white.
In a separate bowl, sift together the flour, baking powder, baking soda, and salt. Add the dry mixture to the butter and eggs in three batches, alternating with the yogurt, beginning and ending with the flour mixture.
Pour the batter into prepared pan. Bake for one hour or until a skewer comes out clean. Leave to cool in the tin for ten minutes, before removing to a wire rack to cool completely.
Stir together the ingredients for the icing in a small bowl. Spread the icing over the cooled cake and serve.