Just sounds like the oven wasn't hot enough OR did you use dried yeast instead of fast acting instant yeast?
Very high heat is crucial here because the steam created in the oven dish by the wet dough gives the loaf that open texture and crust. So preheat everything (oven dish with lid on) at MAX for at least 30 mins. My oven and cookware doesn't really get past Gas Mark 9 450 F (laser thermometer) and it dropped 50F quickly so speed is also key but take extreme care or you'll loose your fingerprints rapido at that heat.
I found manipulating the wetter dough a little tricky to handle initially, it should 'flow like lava' you cannot roll or kneed this like a traditional dough.
After the first overnight proving it should look bubbly and wet, all you can do is scrape it out with a spatula or spoon onto a "heavily" floured surface. Flour the dough pat too, with a coating of flour you should be able to manipulate it a little easier, fold it over itself a few times to form a roundish shape it should stiffen a bit and leave to prove again in a covered well oiled bowl for another hour or two.
I try and manipulate the dough into the oven dish without touching and the bread seam pointing upwards as per the instructions. Lid on, max heat for 30, then lid off temp down for another 30.
Hope this helps.