Bring your Brita-filtered water to a simmer and pour over tea bags. Set aside to infuse and cool- about 30 mins. Strain.
Using a hand blender, cream your sugar with your butter until pale and creamy. Beat in your eggs one by one. Add yoghurt and melted chocolate and blend to combine. Add cooled tea and blend. Sift in all the dry ingredients. Blend to combine. Add to greased and cocoa-d bundt tin. Bake for 50 minutes. Leave to cool in the tin for 10 minutes or so, then turn out onto a rack. Microwave ganache ingredients then pour all over your bundt. Set.