A plan of Upper Wern Hir drawn by Cyril Fox.

After the First World War, munitions factories were moved away from London. A large factory was built at Glasgoed and the nearby farmhouse of Upper Wern Hir was demolished to improve security.

Before demolition, the Ministry of Works surveyed the house and its plan caught the attention of Cyril Fox. His interest in this hall-house led to the creation of Monmouthshire Houses.