In a large bowl, whisk together bread flour, yeast, sugar, salt, cinnamon, and mixed spice.
Add warm milk, egg, melted butter, and orange zest. Mix to form a dough, then stir in the sultanas.
Knead until smooth and elastic. Place in a lightly greased bowl, cover, and let rise until doubled.
Turn dough onto a lightly floured surface and divide into 12 equal pieces. Shape into smooth balls.
Arrange dough balls in a parchment-lined baking pan. Cover and proof until puffy.
Mix cross flour with water into a thick paste. Pipe lines across the buns, then pipe lines the other way to form crosses.
Bake until golden brown and cooked through.
Warm apricot jam with water and brush over hot buns. Cool slightly, then serve.
