150gm active Levain / starter
820gm flour comprising:

550gm Shipton Mill Traditional Organic White flour
200gm Shipton Mill Organic Wholemeal Flour
60gm Spelt Flour
10gm Diastatic Malt Flour
10gm pink salt
630ml water, ideally filtered

Prepare Levain and leave in warm place
Meanwhile mix flour in large bowl
After an hour or so warm water to around 27 deg and pour into mixing bowl
Tip in flour and mix until all water is absorbed
Cover bowl with damp cloth and leave in warm place to autolyse

Just before starter activity is at its peak, sprinkle salt on autolysed flour and pour in your levain.
Mix by hand and spatular. Do not over do it, ots of kneading is not necessary, just thorough mixing
Cover with damp cloth and leave in warm place like airing cupboard for 15 min

Fold dough gently, rotate bowl 90 deg and fold again. Repeat until 4 folds complete. The aim is to gently lift the dough with your hands just far enough off the bowl to fold it over itself, retaining gas bubbles as they form and allowing the gluten stinginess to form

Cover bowl and return to warm place. Repeat entire folding process again after 15 min
Repeat again after a further 30 min

Leave then in warm place, covered with damp cloth, for around 2½ hours. You should see a few bubbles forming. Only experience will tell you when it's ready, too much proving and the dough gets very sticky. The timing is not super critical

Tip dough out onto a lightly floured flat surface. A large board that's been treated with Danish oil is ideal. My dough always needs some encouragement with a spatular to leave the tipped bowl.

Divide the dough into two halves with a dough cutter. I run the blade under warm water which stops the dough sticking to it
make two domes of dough by running the dough blade around each half to form the round. Leave these two on board for 30 min

Make the dough into two loaves. There are many ways to do this, best to research on the internet, The Perfect Loaf is a good place to start: https://www.theperfectloaf.com/guides/
Place the loaves into your bannetons, cover and put in the fridge overnight (for about 12 hours)

Cook loaves in oven, preheated for 45 min at max temp. I use a Forneau oven but again, there are many different ways. I take my dough out of the forneau after 20 min, turn down the oven to medium, and leave it to cook uncovered for a further 20 min. I then repeat the process to cook my second loaf