Warm 3 tbsps of the oil over a medium high heat in a heavy bottomed non stick pan, about 25 to 30 cm in diameter. Add the bacon and saute , stirring from time to time, until it is golden and has rendered its fat. This will take about 5 to 7 minutes.
Reduce the temperature a little, add the red pepper and onion and fry for 5 minutes until softened. Add the garlic and fry gently for a minute. Remove the pan from the heat and let everything cool for 10 minutes.
Preheat the oven to 190 C, 170 Fan Gas 5.
Put the creme fraiche into a large bowl, add about a quarter of the egg and whisk with a fork until well combined. Add the rest of the eggs, whisk in the herbs and chilli flakes and season with salt and pepper.
Fold in the feta, olives and spring onions then add the cooked bacon, pepper and onion and mix well.
Put the frying pan back on the hob over a medium heat. Warm the remaining tablespoon of oil, swirling round the pan. Pour in the frittata mixture and smooth the ingredients out so that they are evenly spread .
Let the eggs cook gently for about 5 minutes, setting from the bottom up. Then put the pan into the oven, covering the handle with foil if it isn’t ovenproof. Cook for about 12 minutes, until just set and golden on top.
Remove the pan from the oven and let the frittata set and cool for 10 minutes, until it pulls away from the edges slightly, before cutting. Serve warm or cold.