Combine the flour, sugar, yeast and salt in the large bowl of an electric mixer fitted with a dough hook. Mix until ingredients are combined. Add the milk, butter and eggs and continue mixing for 6-8 minutes until smooth, or when pressed in it bounces back out (Alternatively, mix in a large bowl and turn out onto a lightly floured surface and knead by hand). Place dough into a lightly oiled bowl, cover with cling wrap and set aside for 1 ½ hours in a warm place or until doubled in size.
Meanwhile, combine the sugar, butter and cinnamon, breaking up any lumps in the sugar.
Remove risen dough to a lightly floured surface and roll out to a 55 x 24cm rectangle. Spread cinnamon mixture over the dough, leaving a 2cm border from the edges. Use a spatula or palette knife dipped in hot water to help spread. Roll up from the long edge to form a long roll. From the top (short) end of the roll, cut the roll into 3 even sized strips. Starting at one end, plait the pieces, whilst turning upwards to expose the cinnamon to the top. Transfer to a lined oven tray, wrap around into a wreath shape, cover loosely with a clean tea towel and set aside for 45 minutes.
Pre-heat oven to 190°C (170°C fan-forced). Place wreath into the oven and cook for 25-30 minutes until golden and risen. Allow to cool for at least 30 minutes before drizzling with icing.
Whilst the wreath is cooling, whisk together the icing sugar and milk until smooth. Drizzle over the wreath and serve.