RE wood: oak is actually slow burning, ideal for keeping an oven or fire going all night, but gorse (dried ) is a traditional peasant fuel for bread ovens. Heats very quickly, gets the temp up. Bread is supposed to be cooked on a falling temperature, so burning gorse then raking out the ashes and slinging in the bread then blocking up the doorway is an old tried and tested way. Not by me, but I have seen it done...good luck