Place five of the eggs in a saucepan and cover with cold water. Bring to the boil over high heat, then reduce heat to medium and simmer for 3.5 minutes. Towards the end of the cooking time prepare an ice bath (Note 2).
As soon as the eggs are done crack the shells slightly then put in an ice bath (Note 3)
While the eggs are boiling, finely slice the parsley and spring onion, and remove the thyme leaves. Place in a medium sized bowl.
Squeeze the sausage meat from its casing, and place the meat in the bowl with the herbs.
Use cold wet hands to combine the meat and herbs. Divide into five equal portions (Note 4), then roll out into a round flat shape (Note 5).
Get your breading ingredients ready by placing the flour, remaining two eggs and breadcrumbs into separate bowls (Note 6). Beat the eggs.
Shell the eggs under cold running water (Note 7), then dust with the flour.
Heat the oil over high heat in a deep frying pan. Use enough to come about halfway up the eggs.
While the oil is heating, use cold wet hands to wrap the meat around each egg, smoothing the edges to ensure the egg is fully enclosed.
One by one, dunk into the egg wash, then dip into the breadcrumbs. Ensure each egg is fully coated.
Once the oil is hot (Note 8), place the balls into the frying pan, cook over medium-high heat for 8.5 minutes, turning regularly. Cook in batches if necessary. Remove the cooked scotch eggs from oil and drain on crumpled paper towels.
Make the sauce by mixing the sour cream and horseradish in a small bowl.
To serve, cut the scotch eggs in halves or quarters, then eat with the sour cream and horseradish sauce.