For the waffles, preheat a waffle maker to a medium setting. Preheat the oven to 140C/275F/Gas 1. Place a large wire rack onto a baking sheet and place in the oven to warm.
Mix the flour, baking powder, salt and sugar in a large mixing bowl. Whisk in the eggs, milk and butter until well combined.
Ladle some of the batter into each well of the waffle maker, close the lid and cook for five minutes or until golden-brown and crisp. Repeat the process until the batter is used up, keeping the cooked waffles warm on the wire rack in the oven.
For the hollandaise, melt the butter in a saucepan and bring to a simmer.
Place the lemon juice and vinegar into a separate small pan and heat until just boiling.
Place the egg yolks into a food processor with a pinch of salt. With the motor running, add the hot lemon and vinegar in a steady stream then slowly add the melted butter until it is all incorporated. Remove the sauce from the processor and season with sea salt and freshly ground black pepper.
For the poached eggs, bring a pan of salted water to the boil and add the vinegar. Whisk the water to create a whirlpool and once settled, carefully crack an egg into the water. Simmer for 2-3 minutes, remove the poached egg with a slotted spoon and place onto a plate to drain. Repeat the process with the remaining eggs.
Heat a frying pan until hot, add the bacon and cook until crisp on both sides. Drain the bacon on kitchen paper.
To serve, place the waffles onto the serving plates, top with the poached eggs and bacon and finish with a drizzle of hollandaise sauce and the chopped chives.