Line 1-2 oven trays with baking paper and set aside.
Fry the bacon pieces in a frying pan, until crisp. Transfer the bacon to a plate to cool and discard any excess oil. You can place it in the fridge or freezer for a short time to speed up this process.
Whisk the self-raising flour, baking powder, curry powder, salt, chives and thyme together in a mixing bowl until combined.
Add the chilled butter and use your fingertips to rub the butter into the flour, until it looks crumbly, like breadcrumbs. It’s ok if there are still some small lumps of butter. Alternatively, you can use a food processor for this step.
Add the grated cheese and place the mixture into the fridge to keep cold while you prepare the buttermilk.
In a small bowl, whisk the chilled buttermilk and egg yolk together until combined.
Make a well in the middle of the flour mixture. Add the buttermilk and egg mixture and the cooled bacon and mix until the dough clumps together.
Add the dough to a lightly floured bench and shape it with your hands. (Don't overwork the dough).
Use a rolling pin to roll the dough to about 2cm thickness.
Use a 6cm round pastry/scone cutter) to cut out 12 scones. After cutting a few scones, you will need to bring the dough back together with your hands and re-roll until the dough is all used up.
Place the scones onto the lined baking trays and use a pastry brush to add a little extra buttermilk (or some milk or melted butter) over the top of the scones.
Place the scones back into the fridge while you pre-heat the oven to 200°C/392 F.
Bake for 18-20 minutes, or until golden brown and fluffy in the middle. Cooked scones will have a "hollow" sound when tapped on top.
Serve hot, straight from the oven, topped with butter and some chilli jam or green tomato chutney.