I have now reached, what I think is the ultimate recipe (based on my better sourdough recipe (on page 25 if you've got the book):
400g strong white bread flour
100ml sourdough starter
275ml filtered water
Make a sponge mixture of half of the flour and all of the starter and water and leave to ferment overnight in the mixing bowl covered with clingfilm.
In the morning add the other half of the flour (and a pinch of salt if you wish) and mix on the slowest speed for five to ten minutes until the dough looks smooth and silky.
Use a spatula to scrape it out into a Lekue (or bread tin) as it's too runny to form into a loaf. Put it in the over covered with clingfilm, to rise for about two and a half hours or roughly doubled in size.
Remove clingfilm and bake at 220C (180C fan) for 30 minutes.
Remove loaf from Lekue and bake for another 25 minutes until nice and golden.
Turn oven off and leave the loaf in the cooling oven for another 5 minutes, then place it on a rack to cool. This is the one I made yesterday morning: