Preheat the oven to 220 °C (fan oven 200 °C). Sieve the flour, baking powder, baking soda, salt and mustard powder into a bowl. Mix in the mustard seeds and cheese. Add buttermilk and milk and work everything into a soft, sticky dough.
Work the dough on the floured worktop to a round shape (Ø 22 cm), place it on a lightly floured baking tray and cut it into 8 cake pieces. Pull the pieces apart, dust lightly with flour and bake for 20 minutes until golden brown.
In the meantime, place the cherry tomatoes in a small ovenproof dish, drizzle with olive oil and season with salt and pepper. After 10 minutes baking time, add the farls to the oven and bake for 10 minutes.
In the meantime, heat a (grill) pan at high temperature until it smokes. Reduce to medium heat and fry the bacon in it until crispy. At the same time, fry the fried eggs in a second pan in sunflower oil to taste.
(We like crispy edges and still liquid egg yolk.) Season with salt and pepper.
Remove the finished farls from the oven, cut a pocket in each piece from the top, butter them and fill them with bacon and eggs. Serve with the tomatoes.