Combine the flour, sugar, yeast and salt in a large mixing bowl. Keep the yeast and salt at separate sides of the bowl. Roughly mix to combine. Make a well in the centre and add the water, milk, eggs and butter. Use your hands to mix to a dough. It will be very sticky and wet, but don't be tempted to add more flour. Very lightly oil your hands and work surface and knead the dough for a good 10 minutes, or if you're lucky enough to own a food mixer, save your arms and use it!
When the dough is very smooth, soft, bouncy and elastic, it's ready. Place into an oiled bowl, cover with cling film and leave to prove for 1-2 hours, or until doubled in size.
When the dough is ready, knock the air out by kneading lightly for 30 seconds or so. Divide the dough into 10-12 even pieces.Roll the pieces of dough into balls (a lightly floured surface comes in handy here) and place on lined baking trays. Cover loosely with oiled cling film or a clean tea towel and leave for around 45 minutes -1 hour until the dough has doubled in size again. While you're waiting, Heat oven to 200C and place a baking tray at the bottom of the oven.
When the buns have doubled in size, brush them all over with the beaten egg glaze.Pour a cup of water into the baking tray you placed at the bottom of the oven earlier (this will keep the buns moist while baking and give them a lovely soft crumb.