Place the flour and salt into a large mixing bowl and stir until thoroughly combined. Make a well in the centre of the flour and pour in the yeast.
Warm the milk and butter in a small saucepan until the butter is melted and the mixture is lukewarm. Pour into the flour mixture, add the egg and stir thoroughly until the contents of the bowl come together as a soft dough.
Tip the dough onto a lightly floured work surface and knead well for five minutes, until the dough is smooth and elastic.
Place the dough into an oiled bowl and leave to rise, covered with a damp tea towel, for one hour or until doubled in size.
Tip the dough out onto a lightly floured work surface. Roll out dough into a rectangle about 30x20cm/12x8in.
Brush all over with the melted butter. Evenly sprinkle the orange zest over the buttered surface, followed by the sugar, cinnamon and dried fruit.
Tack down the long side of the dough rectangle nearest to you by pressing it down onto the work surface with your thumb. Roll the opposite long side of the dough towards you quite tightly, until the roll is complete and tight. With a sharp knife cut into thick rounds - about 4cm/1¾in.
Grease a deep roasting tin or baking tray thoroughly with butter.
Place the buns, cut side up, into the greased baking tray leaving about 1cm/½in of space between each one. You want them to be close enough so that when they rise further and then bake, they will bake with their sides touching. They can then be pulled apart and you get a lovely soft edge.
Leave to rise for about 30 minutes in a warm place.
Preheat oven to 190C/375F/Gas 5.
When the buns are ready, put them in the oven and bake for 20-25 minutes until golden-brown. Check after 15 minutes or so and cover the buns with foil if they are getting too brown.
Remove the buns from the oven and let them cool slightly before transferring them from the tin to a cooling rack.
Melt the jam in a small saucepan with a splash of water until smooth. Brush the jam over the buns to glaze and allow to cool.
Mix together the icing sugar, orange zest and two tablespoons water. Drizzle the icing over the cooled buns and allow to set before serving.