I just found this great listing of Fireplace design in a bunch of houses at the Weald and Downland museum.
It includes a description of the Poplar Cottage inglenook, which I used as a basis for the kitchen.
Unfortunately, it includes the following;
We are not certain how the smoke escaped at the top: we have reconstructed the gable with a small triangle open at the top, but it is possible that there was a structure like the top of a chimney to allow the smoke to escape vertically.
Also, I wish I’d worked out how to include an oven in the design of the hearth, like the 15th C House from Walderton