Update on the door. Had another curing fire in the oven yesterday and while not up to cooking temp the oven was quite hot . Cooked some snags over the coals and then pushed the coals to the centre of the oven and put the door in place. This morning the oven and inside of door was still quite hot with no charring at all. Couldn't fire today as weather is a bit damp but so far so good with the door.