Grease a 27cm x 18cm cake tin with a little butter. Put the bread mix in a large bowl. In another bowl, whisk the sugar and egg together. Add to the dry ingredients with all but 2 tablespoons of the milk. Mix to a soft dough, adding the remaining milk, if needed.
Turn out onto a lightly floured surface and knead the dough for at least 15 mins, until it feels smooth and elastic. Roll the dough out into a rectangle about 25cm x 35cm.
Spread 25g softened butter over the dough, then scatter over the dried fruit. Roll up tightly like a Swiss roll from the long end and cut into 12 rounds. Arrange in the tin, cut-side down; 3 to a row. Cover with lightly greased cling film and put in a warm place for 45 mins, until well risen.
Preheat the oven to 200°C, fan 180°C, gas 6. Bake the buns for 25 mins or until golden. Remove from the oven and brush with the honey and sprinkle with the pistachios. Cool in the tin for about 10 mins, then eat warm.