Combine psyllium husk and water in a large mixing bowl or stand mixer and stir until the psyllium husk has been absorbed by the water. Allow to gel for 3-4 minutes.
Add olive oil, sugar and mix in until smooth.
Whisk the potato starch and chestnut flour together with the salt then add into the mixing bowl and combine.
Finally add in the starter and mix for at least 5-10 minutes until the dough comes together.
Turn the dough out onto a smooth and clean work surface. Roll the dough around using your hands until the dough forms a smooth ball with as few cracks as possible as these will appear on the finished bread.
Line a banneton with a linen or muslin cloth and flour generously with brown rice flour.
Gently lift the bread dough ball and place it inside the banneton nice side down (as it will be flipped later).
Cover the banneton loosely with oiled cling film.
Place the bread bread somewhere warm with a moist atmosphere for between 1-4 hours. The dough should rise by about a third.
Pre-heat the oven to 220°C/ 200°C fan assisted oven / gas mark 7 at least 1 hour prior to baking. Place the dutch oven fitted with its lid into the oven at the same time to heat thoroughly.
Once the bread is proved, remove the cling film and place a length of parchment or bread sling over the top of the bread and carefully insert the loaf onto the sling.
Lower the sling with the bread on it gently into the dutch oven. (The bread is baked on top of the sling)
Bake for 1 hour.
Remove the lid and bake for further 10 minutes to finish browning. Remove from the oven, take the bread out of the dutch oven using the sling and slide onto a cooling rack to cool.
Leave to cool completely before cutting to avoid gumminess.