In a large bowl, whisk together the flour, sugar, tea, baking powder, and salt.
Grate the frozen butter into the flour mixture. Mix it in using your fingers (or a pastry cutter) until all the butter is covered in flour and you have pea-sized lumps. Place the bowl in the refrigerator or freezer while you prepare the wet ingredients.
In a medium bowl, whisk together the coconut milk, egg, and vanilla. Pour the wet mixture into the dry ingredients. Mix together to form a crumbly dough.
Transfer the crumbly dough to a lightly floured work surface (or can do this directly in the bowl). Knead the dough until it comes together. Transfer the dough ball onto a baking sheet lined with parchment paper and form it into an 8-inch disc. Cut the dough into 8 equal wedges using a bench scraper or knife.
Place the scones in the fridge or freezer for 15 minutes before baking and preheat your oven to 400ºF/200ºC.
Space the pieces out so there's a bit of room between each one and brush the tops of the scones with a little coconut milk. Bake for 15-20 minutes or until lightly golden brown on the edges. Remove from the oven and let cool.
Add the powdered sugar, lemon zest, orange zest, and lemon juice to a small bowl. Whisk until combined then brush the tops of the cooled scones with the glaze.