Heat the olive oil in a frying pan over high heat. Cook the bacon until crispy, remove from the pan and place onto paper towel. Set aside.
Fill a large pot with water and bring to the boil over high heat. Add the potatoes. Once the water starts to boil again, cook the potatoes for a further 5 minutes. Drain and set aside to cool completely.
Place the eggs into a saucepan and cover with cold water. Bring to the boil. Turn the heat off and cover with a lid. Leave for 12 minutes. Drain the water, allow to cool slightly and then peel the eggs. Chop into small pieces.
To make the dressing, whisk the sour cream, mayonnaise, dijon mustard, salt and pepper in a bowl.
To assemble the salad, place the potatoes into a large bowl. Add the chopped eggs, bacon and spring onion.
Pour over the dressing and carefully mix to combine.