Bunwell postmill was found by Harry Apling to have been mentioned in the Petre Catalogue that is held in the Norfolk Record Office. This is a paper bound book, petition to the Keeper of the Great Seal, by John Lewthwatt of North Creake, late of Reedham, yeoman, against Sir Richard Berney of Reedham, bt., relating to a windmill & land in Bunwell c.1639.